Neuro's Demon World Notes!
Consolidating my notes I've shaken out of Neuro over the time I've been poking at him to fill in blanks. And he has a LOOOTT of blanks. I've attempted to check this against the way him and his devices work in canon (as little as is explained there) as much as possible, and there's some things I didn't quite go into here that I've shook out of him. Posting this here partly for anybody that's horrendously curious/bored, and partly so that if mods at Cfeit/Blip/SP ever get curious about what environment he's coming from (and get bored/have time on their hands) they can poke through it.
Be forewarned, this was 6 pages in Openoffice.
- First off, check assumptions about basic laws of reality, physics, and biology at the door. Sounds simple, but there's a LOT that's very easy to take for granted in that regard, and not only would the demons be an entirely different, alien, sentient race, but they're part of an environment that is alien in a sense beyond just "Methane-based sky".
-The plane is a place of chaos, and a HELL of a lot of energy-shifts and power. (No pun intended.) Even basic things, like gravity, are arbitrary and may change within the span of a few feet worth of distance, much less a few miles.... and some areas are less stable than others as far as what laws of reality are in effect when. There's floating rocks/etc., water that flows upward, and generally any number of things that may not make sense, as well as things like flows of electricity, light, other energy things and non-solid things as "landforms"...and more metaphysical-weird shit being plainly visible and part of the landscape as well. Extremes of temperature, atmosphere, weather, and things like random clouds of toxic gasses (or random clouds of perfectly harmless things) are also just as likely.
- From there, we get into living things... and things get more complicated.
Not everything living there is a "demon" per se, in the "intelligent, speaking, sapient, etc." sense; there's a lot of living things that run the gamut of "wildlife". (Note that the Fridays actually get some explanation as demon-world insects, while there's that fish that pops up periodically - wildlife!) First thing to not take for granted - not all "living" things are made of animate matter! There's "elemental" type things that're living stone, fire, electricity, sand, water, other-forms-of-energy, et al; cases where dead remains get reanimated as another creature; and construct-ish creatures that're just as alive as anything else.
- So, used to those species boundaries? Nice cozy categories defined by what can and can't reproduce and is and isn't related/similar?
Forget them.
First off, things can end up changing drastically in class, type of life form, and even niche on the larger food chain/scheme of things over their lifetime, depending on anything from intervention by other entities there changing them, to active attempts at changing their own nature or feeding off something that would change them, to simple environmental glitches and getting caught in the wrong power spike of the wrong energy type at the wrong time.
Second off, with everything in a state of flux anyway, when you do get into traditional reproduction, the life-form types of the "parents" don't really matter or have to correlate beyond just some vague ability to interact on that level.
Thirdly, you can't even rely on parental lineages; inanimate objects can get brought to life and living things can be changed into inanimate objects.
Now we get into defining the "Demon" race...
Which is basically just a catch-all for the race of entities that're sapient, speaking, have a form of society, and dwell in that plane. They run the gamut of entity types like any other "living" thing, and include elemental types, astral/spirit types, "animal"/creature types, plant types, 'construct' types...no, there isn't a simple answer.
There's basically three sources for new demons -
One being "traditional reproduction", with parents of one fashion or another.
The second and third would be "Fledging" from other sources, whether by an existing demon or some natural event (get caught in the right storm, and get altered, etc.); some Fledges start out as inanimate objects, Tools, or "animals", others start out as other sentient races from other planes. For the ones that start out as another sentient being, the closest comparison would probably be a stereotypical vampire "Sire and Childe" idea - A demon decides that someone is potentially useful or gets attached to someone for some reason, and converts them over. (The other kind of fledge is a bit harder to wrap head around in a way, since it ranges from Doctor Moreau-esque "this used to be a plant/animal and has some concept of being a living thing", to "This was a weapon a week ago and is now some form of demon".) Animals, objects, and landforms that were “accidentally” fledged by environmental effects and have no “parent” only add to the confusion, really.
In just about any case with something that's not somehow -born- a Demon, it's basically a matter of getting enough of the basic chaotic energy of the demon world fused into the being's system and aura, that it takes over and alters the rest of the being, causing a metamorphosis. For a fledge converted intentionally, it means a parent did some sort of controlled Marking and contributed their own power to the change.
Unfortunately for sanity of making sense of things, the metamorphosis is a mix of the energy and marks/directions being added, the Fledge's own energy and predispositions, the environment at the time, and what outside pressures or stresses might be influencing any of the above, so there isn't any guarantee that the fledge will be a similar type of being to the parent in terms of "phenotype", diet, etc., much less if they'll be animal, vegetable, or mineral in their full-out "demon" form. Most Fledges that used to be some kind of sentient being or animal maintain the ability to shift back down to their original forms, and many demons in general can learn some limited-range shapeshifting. (The full-out, monstrous, ZOMGDEMON!! shapes take a lot of ambient energy to support, for one thing; a demon intending to do much on the mortal plane needs either a form that's less energy-intensive, or to learn some kind of “skin” trick to form a buffer between themselves and the mortal plane. Ones that get summoned to the mortal plane often end up crashing into such a state reflexively, whether they knew how to do it before or not. If the answer is “not”, then yes, it -is- basically a shock to the system the first time and very uncomfortable/painful.)
How much of a shock the fledging process is varies a lot depending on several things. One is the fledge themselves - If there's a lot of nervousness or resistance, or even reflexive panic-twitches, it does make it much harder on the fledge. Another is if/how badly the “parent”'s energy clashes with the fledge's. The parent also has some control over the process; a rushed changeover is a bit more of a system-shock than a gradual one, and the parent's skill at fine energy work makes a lot of difference. Prior Marks or other interference by the parent and prior exposure to a lot of that sort of energy makes the transition easier. (It -is- almost impossible to do if there isn't some agreement from the fledge.)
That being said, it basically is having foreign energy brought into the fledge's system that is rewriting their basic nature and altering their body and spiritual makeup; it's almost never just a smooth transition, and it tends to be kinda noticeable when you're becoming a very different kind of creature. Also, there isn't exactly an instruction manual, and other-race fledges do have to deal with unpredictable shifts in instincts/lag between the change happening and new instincts kicking in. The parent isn't even capable of always being that much help, since THEY only have so much control over it and it may require a trial and error period to figure out little things like, “What does the Fledge EAT?”. (It -is- possible to pass on some things like lesser Titles, some Tools, some degree of power level, and sometimes some powers to a Fledge, the last one being the haziest, since innate abilities tend to be very specific to a given individual's energy structure and may not work with someone else's system - in which case attempts at passing some power or another down just sort of don't do anything.)
Oh yes - different demons don't always have the same food source. Demons are very high-energy, planar entities; while some of them do have their feeding habits tied to some kind of physical focus or need to actually ingest something to get energy, the main part of the diet is -always- one form of energy or another. This could be anything from raw life force (either general, or specific “can only feed on plants/animals/humans/etc.), elemental energies, emotional or spiritual energies, electricity, light, ooor stranger. Demons that don't have to actually ingest something to eat usually “feed” via proximity or contact; some require physical contact with a food source, others are capable of using tendrils of their own energy to reach out and draw the energy to them.
An exception to this is the cannibalism rule...although that sort-of requires an explanation of Titles and how creatures from that plane grow in power. (Basically, any outside source that ends up causing a jump in power level or gaining a Title of some kind is also something that can be fed on.)
There is some degree of gradual growth within a certain range; generally speaking, of creatures in the same vague level or category, an older one will be more powerful than a younger one. This has some limitations; there's a ceiling on it for most creatures, and it's never enough to really change the nature of a creature or change what sorts of abilities they have.
It is possible for some environmental effects to end up dumping power on a creature, or even changing parts of it a'la the Fledge interaction.
The more active means, usually, is to take power from some other creature, whether wildlife or another demon. This functions somewhat proportionally; a Demon taking power from a weaker creature may not gain much more than a meal (or a snack, if the difference in power is great enough)...if it's a creature that's only slightly weaker, there may be some energy/aura-growth or claiming of some Title or new power... if it's something on an equal footing, or a more powerful creature, then it's usually a fairly sizeable jump in evolution. (Also, if the victim is a demon with Tools, control of those Tools transfers.) The catch is that it's permanently claiming and feeding off the spiritual energy and structure of the victim - if the victim has any ability to defend themselves, it won't work, and if they weren't dead before they were fed off, they are after.
This, by the way, should explain a LOT about demon society and social interactions; they -have- one, and do form societies, even the occasional city, but the character of interactions and connections is very, very different from human society, because they -are- inherently cannibalistic. Some groups do form “clans” and alliances or authority-structures that can last for millenia, but there is always that chance that someone within such a group will decide to pick off another, and with demons outside a “clan” or group, all bets are off. The one main thing generating stability is predatory conservation of energy and survival tactics; having too many enemies without at least some allies gets dangerous, and there's always the question of how much energy and risk is involved in taking down a given target vs. how much is gained if you win. Typically, clans or “political” groups will band together quickly for defense against outsiders...but also have some kind of unwritten protocol about personal advancement, where assassinations within the group are only a problem if they disrupt larger agendas too much, disrupt the agendas of the more powerful demons that're in charge and still living, or leave the group too vulnerable to outside attack. (These fall apart and turn inwards on each other frighteningly easy sometimes.)
“Titles” would basically just be some kind of static energy-structure that can be passed between individuals and carry some degree of power; in a way they're like crafted parts of an aura that're usually tailored to some purpose or another. While they're part of what's claimed when a cannibalism is pulled it is sometimes possible for them to be given away. (...basically, if the Demon carrying it has outgrown it for whatever reason, they can grant it to a weaker demon; if it's a decent part of their energy or powers, then removing it -will- kill them.) Generally, Titles are given away in the circumstances of a demon that's gained some degree of power and claimed quite a few of them from feeding off others, granting some of the smaller ones to weaker demons that're under their control somehow (whether by alliance or whatever) to make them more useful or cement ties. (There are occasional cases, in more stable chains of command, where a more middle-ranked demon is basically contracted to give all or part of Titles/Tools gained from targets to a more powerful master, who may then re-distribute it wherever they find it most useful - a tactic that makes it easier for the stronger demon to maintain power; there's fewer and fewer such groups, but stable alliances do serve the weaker demons in the group by giving more protection against outside threats, for as long as they last.) They can be kept “dormant/inactive” indefinitely after being claimed or gained; while there's only limited benefit from an inactive Title, it does make it impossible for others to tell the Title's there, which can make it a survival tactic if there's too much competition as of gaining it. Some of the more powerful demons can shape power into new ones, again usually granted as part of making minions more useful or part of some kind of bargain.
Tools are something of a special case where things get yet messier. Generally speaking, Tools are some sort of entity, object, or activated power that is a distinct whole, that can be “carried” within a demon's aura as an energetic presence and (if it has a solid form) manifested whenever needed. They draw off the power of their owner when active. Some of them are basically symbiotic other creatures, that may or may not have the potential to be SOMEWHAT independent, or at least use outside “food/power” sources to draw less off their owner - usually, the larger/more powerful the “creature”, the less likely it is to be able to do so, or the more stringent and specific the circumstances it can under are. Too much independence is generally avoided in anything much bigger than, say, the Fridays or tracking bug type Tools - because more powerful ones would have too much potential to break away or start bucking control. Some of them show up more as objects and things more easily seen as tools per se; these -do- take power as long as they're manifested solidly. The least obvious ones would be things like Blind or the other temporary invisibility trick, where it's not even anything with a solid form. For the most part, Tools are not a necessary part of a Demon's aura or a direct impact on their health (besides whatever drain on energy goes into using them); they can be freely given to any other entity with the ability to control them and a strong enough aura to support the Tool and survive feeding it power to use it. (ofc, giving a Tool away is usually less motivated by benevolence and more motivated by bargaining and potential for gain by doing so.)
Tools do have multiple possible origins, ranging from things crafted by a Demon (which...doesn't always mean it's an 'object' tool; most “power/energy” tools are crafted, and it's possible to create symbiotes from the right materials and magics), to things that were found and adapted into Tools, to other entities that were stripped down to some extent and made into one. (The Fridays obviously fall into this last category and aren't very far from their original state, really; the Imperial Weapons... are -mostly- the remains of the previous Emperors, converted into Tools after the “successor” cannibalized them.)
On demon society - there are some stable “clans” and chains of authority, even a few cities and larger settlements. It isn't so much that any of these have any real set laws per se, as there's general customs and guidelines...which aren't enforced so much out of “these are the rules in this area”, as “this area is so-and-so's territory and this is how they say things go”. If a more powerful demon wants to maintain control over individuals or areas outside of their own immediate surroundings, it usually ends up meaning they get weaker demons maintaining their power over their territory and doing things for them in exchange for some form of protection and/or power. A demon that's powerful enough and smart enough about it can end up with a fairly large sphere of influence, but it largely depends on how well they maintain control over their underlings and how reliable said underlings are about keeping their side of the bargain. Most “lords” or higher deal with that issue by making it a Very Very Bad Idea to cross them or -not- hold up your end of a fealty bargain/other deal, possibly mixed with playing the underlings off one another.
Cities and such tend to survive based on a mix of one or more powerful Lords/Kings/Emperors holding sway over it and maintaining some form of order, and a sort of “watering hole” truce. (Granted, if you think human cities are dangerous if you go down the wrong alley alone...) Typically it's acknowledged that there is some gain out of NOT killing each other and maintaining trade of various sorts, exchanging information, and the like, but it really only lasts as far as self interest... maybe even “enlightened self interest” if you're lucky, and how interested the local Demon In Charge is in the value of trade etc..
There's a few notes of history that would be basic-important knowledge.
*) There is a “higher plane”. The beings from there are also basically high-energy/strong-spirit/etc. Like demons, but are more stable and tend toward the opposite end of the spectrum. (This isn't to say that they're always fluff and sweetness and light... think old testament angels and what a lot of mythos's gods are like.) They don't get along with the lower planes, but basically are “further away/harder to get to” than the mortal plane, or at least harder to get to without a lot of power, possibly some static structures, and using the mortal plane as a stepping stone.
*) There was a time in the past when the higher and lower planes would directly and openly mess with the mortal planes. They also happened to be at war with each other during this time, which meant that areas of the mortal plane ended up battlefields sometimes, and humans got used as pawns back and forth, as each side tried to get the locals to help them and hinder the other side. Fragments of stories about this probably account for a lot of the weird shit in mythology. This gradually tapered off, since there was a pretty major attrition factor going on with both sides on manpower/resources, as well as more stable power bases being built in the mortal realms that at least made the obvious battlefield thing happen less.
*) No, divine creatures do not really convert well to demons without getting altered pretty substantially first, and vice versa. Opposing base energies and all.
*) No, divine types can't really be “cannibalized”, although a little bit of energy can sometimes be scraped out of their auras by a demon with the right diet; opposing base energies again.
*) Yes, divine-power hurts demons like a BITCH and vice versa.
*) No, they don't survive very well for long periods of time in the opposing plane without the background energy either eroding at them and slowly killing them, or warping them.
*) That period ended with a sort-of treaty (which Neuro was alive for, albeit the margin of “period of his life pre-treaty” is much shorter than “post-treaty”) that left the mortal plane as a buffer zone, with a list of rules and conditions on either side interfering with/traveling to the mortal plane; anything done by one side or the other that's too much like trying to build an old-style power base among mortals or set something up that COULD potentially be used to strike at the other side would be a breach of treaty and at least get the offender pretty heavily targeted by the other side, if not restart the war. Note that the offender's own side may not help them - since the divine beings actually do take the treaty and trying not to destroy the mortal realm in the crossfire fairly seriously, and most demons with any measure of power wouldn't feel that great about their chances picking a fight with the higher planes when there's no guarantee the rest of Hell won't sit on the sidelines with lemonade and say “Eh, it's not worth the risk to us to help him, you can have him” - or even possibly sell them out as part of some agenda/gambit to take a shot at claiming their power. (Kill/cannibalize them, you get stronger, the divine-angelic types go away and aren't a threat anymore - win/win situation.)
*) This makes an important point in demonic history and the state of power structures - most of the large-scale Empires and cities date back to pre-Treaty times, and were forged out of necessity and the sort-of instinctive “we can kill each other but outsiders killing us off = time to take a break from that to aim at them” reflex. It also has meant that, since the Treaty, the origins of successive generations of Demons has changed; with less access to the mortal plane or other areas, there's a lot fewer Demons that started out as humans or being NOT native to Hell... on a large scale, the demon race's been growing -more- alien.
*) The old Empires and cities have been eroding and falling apart since the Treaty. On a more obvious level, the lack of outside threats means that there's less reason for demons to -need- any large collective power structures; they survive mainly out of habit and the ability of surviving Lords, Kings, and Emperors to maintain power, and often when there's a chunk taken out of a higher-ranking-demon's territory or influence, it's a difficult battle to regain that loss. On a less obvious level, the change in origin has probably had an increasing effect, since humanborn demons would have SOME remaining social instincts and habits that would be less pronounced or absent in Hell-born demons. The end result is that larger society is slowly fragmenting and becoming more and more chaotic and prone to infighting and backstabbing.
Neuro's home territory was an Empire centered in a place referenced as “the Brass City”; it had been one of the stronger Empires pre-treaty, and one of the major frontline powers in the war with the higher planes - and initially, it had an honest to god army. The high concentration of warrior/hunter focused demons that made it so powerful during the wars, also made it one of the more powder-keg Empires after the Treaty. The Emperor he served under and eventually assassinated, Leviathan, had been in power from some point pre-Treaty. Leviathan had partly maintained power by surreptitiously getting rid of any underling that might get powerful enough to challenge or threaten him; Neuro's reaction to figuring this out was his undoing, since instead of openly turning on Leviathan or leaving, Neuro opted to use Leviathan's playing-underlings-off-each-other tactics to cause enough chaos and wear Leviathan down enough that he could be picked off.
Be forewarned, this was 6 pages in Openoffice.
- First off, check assumptions about basic laws of reality, physics, and biology at the door. Sounds simple, but there's a LOT that's very easy to take for granted in that regard, and not only would the demons be an entirely different, alien, sentient race, but they're part of an environment that is alien in a sense beyond just "Methane-based sky".
-The plane is a place of chaos, and a HELL of a lot of energy-shifts and power. (No pun intended.) Even basic things, like gravity, are arbitrary and may change within the span of a few feet worth of distance, much less a few miles.... and some areas are less stable than others as far as what laws of reality are in effect when. There's floating rocks/etc., water that flows upward, and generally any number of things that may not make sense, as well as things like flows of electricity, light, other energy things and non-solid things as "landforms"...and more metaphysical-weird shit being plainly visible and part of the landscape as well. Extremes of temperature, atmosphere, weather, and things like random clouds of toxic gasses (or random clouds of perfectly harmless things) are also just as likely.
- From there, we get into living things... and things get more complicated.
Not everything living there is a "demon" per se, in the "intelligent, speaking, sapient, etc." sense; there's a lot of living things that run the gamut of "wildlife". (Note that the Fridays actually get some explanation as demon-world insects, while there's that fish that pops up periodically - wildlife!) First thing to not take for granted - not all "living" things are made of animate matter! There's "elemental" type things that're living stone, fire, electricity, sand, water, other-forms-of-energy, et al; cases where dead remains get reanimated as another creature; and construct-ish creatures that're just as alive as anything else.
- So, used to those species boundaries? Nice cozy categories defined by what can and can't reproduce and is and isn't related/similar?
Forget them.
First off, things can end up changing drastically in class, type of life form, and even niche on the larger food chain/scheme of things over their lifetime, depending on anything from intervention by other entities there changing them, to active attempts at changing their own nature or feeding off something that would change them, to simple environmental glitches and getting caught in the wrong power spike of the wrong energy type at the wrong time.
Second off, with everything in a state of flux anyway, when you do get into traditional reproduction, the life-form types of the "parents" don't really matter or have to correlate beyond just some vague ability to interact on that level.
Thirdly, you can't even rely on parental lineages; inanimate objects can get brought to life and living things can be changed into inanimate objects.
Now we get into defining the "Demon" race...
Which is basically just a catch-all for the race of entities that're sapient, speaking, have a form of society, and dwell in that plane. They run the gamut of entity types like any other "living" thing, and include elemental types, astral/spirit types, "animal"/creature types, plant types, 'construct' types...no, there isn't a simple answer.
There's basically three sources for new demons -
One being "traditional reproduction", with parents of one fashion or another.
The second and third would be "Fledging" from other sources, whether by an existing demon or some natural event (get caught in the right storm, and get altered, etc.); some Fledges start out as inanimate objects, Tools, or "animals", others start out as other sentient races from other planes. For the ones that start out as another sentient being, the closest comparison would probably be a stereotypical vampire "Sire and Childe" idea - A demon decides that someone is potentially useful or gets attached to someone for some reason, and converts them over. (The other kind of fledge is a bit harder to wrap head around in a way, since it ranges from Doctor Moreau-esque "this used to be a plant/animal and has some concept of being a living thing", to "This was a weapon a week ago and is now some form of demon".) Animals, objects, and landforms that were “accidentally” fledged by environmental effects and have no “parent” only add to the confusion, really.
In just about any case with something that's not somehow -born- a Demon, it's basically a matter of getting enough of the basic chaotic energy of the demon world fused into the being's system and aura, that it takes over and alters the rest of the being, causing a metamorphosis. For a fledge converted intentionally, it means a parent did some sort of controlled Marking and contributed their own power to the change.
Unfortunately for sanity of making sense of things, the metamorphosis is a mix of the energy and marks/directions being added, the Fledge's own energy and predispositions, the environment at the time, and what outside pressures or stresses might be influencing any of the above, so there isn't any guarantee that the fledge will be a similar type of being to the parent in terms of "phenotype", diet, etc., much less if they'll be animal, vegetable, or mineral in their full-out "demon" form. Most Fledges that used to be some kind of sentient being or animal maintain the ability to shift back down to their original forms, and many demons in general can learn some limited-range shapeshifting. (The full-out, monstrous, ZOMGDEMON!! shapes take a lot of ambient energy to support, for one thing; a demon intending to do much on the mortal plane needs either a form that's less energy-intensive, or to learn some kind of “skin” trick to form a buffer between themselves and the mortal plane. Ones that get summoned to the mortal plane often end up crashing into such a state reflexively, whether they knew how to do it before or not. If the answer is “not”, then yes, it -is- basically a shock to the system the first time and very uncomfortable/painful.)
How much of a shock the fledging process is varies a lot depending on several things. One is the fledge themselves - If there's a lot of nervousness or resistance, or even reflexive panic-twitches, it does make it much harder on the fledge. Another is if/how badly the “parent”'s energy clashes with the fledge's. The parent also has some control over the process; a rushed changeover is a bit more of a system-shock than a gradual one, and the parent's skill at fine energy work makes a lot of difference. Prior Marks or other interference by the parent and prior exposure to a lot of that sort of energy makes the transition easier. (It -is- almost impossible to do if there isn't some agreement from the fledge.)
That being said, it basically is having foreign energy brought into the fledge's system that is rewriting their basic nature and altering their body and spiritual makeup; it's almost never just a smooth transition, and it tends to be kinda noticeable when you're becoming a very different kind of creature. Also, there isn't exactly an instruction manual, and other-race fledges do have to deal with unpredictable shifts in instincts/lag between the change happening and new instincts kicking in. The parent isn't even capable of always being that much help, since THEY only have so much control over it and it may require a trial and error period to figure out little things like, “What does the Fledge EAT?”. (It -is- possible to pass on some things like lesser Titles, some Tools, some degree of power level, and sometimes some powers to a Fledge, the last one being the haziest, since innate abilities tend to be very specific to a given individual's energy structure and may not work with someone else's system - in which case attempts at passing some power or another down just sort of don't do anything.)
Oh yes - different demons don't always have the same food source. Demons are very high-energy, planar entities; while some of them do have their feeding habits tied to some kind of physical focus or need to actually ingest something to get energy, the main part of the diet is -always- one form of energy or another. This could be anything from raw life force (either general, or specific “can only feed on plants/animals/humans/etc.), elemental energies, emotional or spiritual energies, electricity, light, ooor stranger. Demons that don't have to actually ingest something to eat usually “feed” via proximity or contact; some require physical contact with a food source, others are capable of using tendrils of their own energy to reach out and draw the energy to them.
An exception to this is the cannibalism rule...although that sort-of requires an explanation of Titles and how creatures from that plane grow in power. (Basically, any outside source that ends up causing a jump in power level or gaining a Title of some kind is also something that can be fed on.)
There is some degree of gradual growth within a certain range; generally speaking, of creatures in the same vague level or category, an older one will be more powerful than a younger one. This has some limitations; there's a ceiling on it for most creatures, and it's never enough to really change the nature of a creature or change what sorts of abilities they have.
It is possible for some environmental effects to end up dumping power on a creature, or even changing parts of it a'la the Fledge interaction.
The more active means, usually, is to take power from some other creature, whether wildlife or another demon. This functions somewhat proportionally; a Demon taking power from a weaker creature may not gain much more than a meal (or a snack, if the difference in power is great enough)...if it's a creature that's only slightly weaker, there may be some energy/aura-growth or claiming of some Title or new power... if it's something on an equal footing, or a more powerful creature, then it's usually a fairly sizeable jump in evolution. (Also, if the victim is a demon with Tools, control of those Tools transfers.) The catch is that it's permanently claiming and feeding off the spiritual energy and structure of the victim - if the victim has any ability to defend themselves, it won't work, and if they weren't dead before they were fed off, they are after.
This, by the way, should explain a LOT about demon society and social interactions; they -have- one, and do form societies, even the occasional city, but the character of interactions and connections is very, very different from human society, because they -are- inherently cannibalistic. Some groups do form “clans” and alliances or authority-structures that can last for millenia, but there is always that chance that someone within such a group will decide to pick off another, and with demons outside a “clan” or group, all bets are off. The one main thing generating stability is predatory conservation of energy and survival tactics; having too many enemies without at least some allies gets dangerous, and there's always the question of how much energy and risk is involved in taking down a given target vs. how much is gained if you win. Typically, clans or “political” groups will band together quickly for defense against outsiders...but also have some kind of unwritten protocol about personal advancement, where assassinations within the group are only a problem if they disrupt larger agendas too much, disrupt the agendas of the more powerful demons that're in charge and still living, or leave the group too vulnerable to outside attack. (These fall apart and turn inwards on each other frighteningly easy sometimes.)
“Titles” would basically just be some kind of static energy-structure that can be passed between individuals and carry some degree of power; in a way they're like crafted parts of an aura that're usually tailored to some purpose or another. While they're part of what's claimed when a cannibalism is pulled it is sometimes possible for them to be given away. (...basically, if the Demon carrying it has outgrown it for whatever reason, they can grant it to a weaker demon; if it's a decent part of their energy or powers, then removing it -will- kill them.) Generally, Titles are given away in the circumstances of a demon that's gained some degree of power and claimed quite a few of them from feeding off others, granting some of the smaller ones to weaker demons that're under their control somehow (whether by alliance or whatever) to make them more useful or cement ties. (There are occasional cases, in more stable chains of command, where a more middle-ranked demon is basically contracted to give all or part of Titles/Tools gained from targets to a more powerful master, who may then re-distribute it wherever they find it most useful - a tactic that makes it easier for the stronger demon to maintain power; there's fewer and fewer such groups, but stable alliances do serve the weaker demons in the group by giving more protection against outside threats, for as long as they last.) They can be kept “dormant/inactive” indefinitely after being claimed or gained; while there's only limited benefit from an inactive Title, it does make it impossible for others to tell the Title's there, which can make it a survival tactic if there's too much competition as of gaining it. Some of the more powerful demons can shape power into new ones, again usually granted as part of making minions more useful or part of some kind of bargain.
Tools are something of a special case where things get yet messier. Generally speaking, Tools are some sort of entity, object, or activated power that is a distinct whole, that can be “carried” within a demon's aura as an energetic presence and (if it has a solid form) manifested whenever needed. They draw off the power of their owner when active. Some of them are basically symbiotic other creatures, that may or may not have the potential to be SOMEWHAT independent, or at least use outside “food/power” sources to draw less off their owner - usually, the larger/more powerful the “creature”, the less likely it is to be able to do so, or the more stringent and specific the circumstances it can under are. Too much independence is generally avoided in anything much bigger than, say, the Fridays or tracking bug type Tools - because more powerful ones would have too much potential to break away or start bucking control. Some of them show up more as objects and things more easily seen as tools per se; these -do- take power as long as they're manifested solidly. The least obvious ones would be things like Blind or the other temporary invisibility trick, where it's not even anything with a solid form. For the most part, Tools are not a necessary part of a Demon's aura or a direct impact on their health (besides whatever drain on energy goes into using them); they can be freely given to any other entity with the ability to control them and a strong enough aura to support the Tool and survive feeding it power to use it. (ofc, giving a Tool away is usually less motivated by benevolence and more motivated by bargaining and potential for gain by doing so.)
Tools do have multiple possible origins, ranging from things crafted by a Demon (which...doesn't always mean it's an 'object' tool; most “power/energy” tools are crafted, and it's possible to create symbiotes from the right materials and magics), to things that were found and adapted into Tools, to other entities that were stripped down to some extent and made into one. (The Fridays obviously fall into this last category and aren't very far from their original state, really; the Imperial Weapons... are -mostly- the remains of the previous Emperors, converted into Tools after the “successor” cannibalized them.)
On demon society - there are some stable “clans” and chains of authority, even a few cities and larger settlements. It isn't so much that any of these have any real set laws per se, as there's general customs and guidelines...which aren't enforced so much out of “these are the rules in this area”, as “this area is so-and-so's territory and this is how they say things go”. If a more powerful demon wants to maintain control over individuals or areas outside of their own immediate surroundings, it usually ends up meaning they get weaker demons maintaining their power over their territory and doing things for them in exchange for some form of protection and/or power. A demon that's powerful enough and smart enough about it can end up with a fairly large sphere of influence, but it largely depends on how well they maintain control over their underlings and how reliable said underlings are about keeping their side of the bargain. Most “lords” or higher deal with that issue by making it a Very Very Bad Idea to cross them or -not- hold up your end of a fealty bargain/other deal, possibly mixed with playing the underlings off one another.
Cities and such tend to survive based on a mix of one or more powerful Lords/Kings/Emperors holding sway over it and maintaining some form of order, and a sort of “watering hole” truce. (Granted, if you think human cities are dangerous if you go down the wrong alley alone...) Typically it's acknowledged that there is some gain out of NOT killing each other and maintaining trade of various sorts, exchanging information, and the like, but it really only lasts as far as self interest... maybe even “enlightened self interest” if you're lucky, and how interested the local Demon In Charge is in the value of trade etc..
There's a few notes of history that would be basic-important knowledge.
*) There is a “higher plane”. The beings from there are also basically high-energy/strong-spirit/etc. Like demons, but are more stable and tend toward the opposite end of the spectrum. (This isn't to say that they're always fluff and sweetness and light... think old testament angels and what a lot of mythos's gods are like.) They don't get along with the lower planes, but basically are “further away/harder to get to” than the mortal plane, or at least harder to get to without a lot of power, possibly some static structures, and using the mortal plane as a stepping stone.
*) There was a time in the past when the higher and lower planes would directly and openly mess with the mortal planes. They also happened to be at war with each other during this time, which meant that areas of the mortal plane ended up battlefields sometimes, and humans got used as pawns back and forth, as each side tried to get the locals to help them and hinder the other side. Fragments of stories about this probably account for a lot of the weird shit in mythology. This gradually tapered off, since there was a pretty major attrition factor going on with both sides on manpower/resources, as well as more stable power bases being built in the mortal realms that at least made the obvious battlefield thing happen less.
*) No, divine creatures do not really convert well to demons without getting altered pretty substantially first, and vice versa. Opposing base energies and all.
*) No, divine types can't really be “cannibalized”, although a little bit of energy can sometimes be scraped out of their auras by a demon with the right diet; opposing base energies again.
*) Yes, divine-power hurts demons like a BITCH and vice versa.
*) No, they don't survive very well for long periods of time in the opposing plane without the background energy either eroding at them and slowly killing them, or warping them.
*) That period ended with a sort-of treaty (which Neuro was alive for, albeit the margin of “period of his life pre-treaty” is much shorter than “post-treaty”) that left the mortal plane as a buffer zone, with a list of rules and conditions on either side interfering with/traveling to the mortal plane; anything done by one side or the other that's too much like trying to build an old-style power base among mortals or set something up that COULD potentially be used to strike at the other side would be a breach of treaty and at least get the offender pretty heavily targeted by the other side, if not restart the war. Note that the offender's own side may not help them - since the divine beings actually do take the treaty and trying not to destroy the mortal realm in the crossfire fairly seriously, and most demons with any measure of power wouldn't feel that great about their chances picking a fight with the higher planes when there's no guarantee the rest of Hell won't sit on the sidelines with lemonade and say “Eh, it's not worth the risk to us to help him, you can have him” - or even possibly sell them out as part of some agenda/gambit to take a shot at claiming their power. (Kill/cannibalize them, you get stronger, the divine-angelic types go away and aren't a threat anymore - win/win situation.)
*) This makes an important point in demonic history and the state of power structures - most of the large-scale Empires and cities date back to pre-Treaty times, and were forged out of necessity and the sort-of instinctive “we can kill each other but outsiders killing us off = time to take a break from that to aim at them” reflex. It also has meant that, since the Treaty, the origins of successive generations of Demons has changed; with less access to the mortal plane or other areas, there's a lot fewer Demons that started out as humans or being NOT native to Hell... on a large scale, the demon race's been growing -more- alien.
*) The old Empires and cities have been eroding and falling apart since the Treaty. On a more obvious level, the lack of outside threats means that there's less reason for demons to -need- any large collective power structures; they survive mainly out of habit and the ability of surviving Lords, Kings, and Emperors to maintain power, and often when there's a chunk taken out of a higher-ranking-demon's territory or influence, it's a difficult battle to regain that loss. On a less obvious level, the change in origin has probably had an increasing effect, since humanborn demons would have SOME remaining social instincts and habits that would be less pronounced or absent in Hell-born demons. The end result is that larger society is slowly fragmenting and becoming more and more chaotic and prone to infighting and backstabbing.
Neuro's home territory was an Empire centered in a place referenced as “the Brass City”; it had been one of the stronger Empires pre-treaty, and one of the major frontline powers in the war with the higher planes - and initially, it had an honest to god army. The high concentration of warrior/hunter focused demons that made it so powerful during the wars, also made it one of the more powder-keg Empires after the Treaty. The Emperor he served under and eventually assassinated, Leviathan, had been in power from some point pre-Treaty. Leviathan had partly maintained power by surreptitiously getting rid of any underling that might get powerful enough to challenge or threaten him; Neuro's reaction to figuring this out was his undoing, since instead of openly turning on Leviathan or leaving, Neuro opted to use Leviathan's playing-underlings-off-each-other tactics to cause enough chaos and wear Leviathan down enough that he could be picked off.