PRE-EDENSPHERE APPEARANCE: It's fair to say that Kisame doesn't blend into the crowd. Even if you disregard his more... unique features, he's almost six foot four in height and powerfully built, which marks him out as unusual in terms of most other characters in Naruto. Add to that the blue skin and hair, gills on face and shoulders, sharpened teeth and distinctly inhuman eyes... then you have yourself a monster. This is reflected in the nickname he bears from his early life in Kirigakure - Monster of the Hidden Mist.
Because the sharpened teeth appear to be something that all members/budding members of the Seven Ninja Swordsmen of the Mist share in the same way that all ANBU have a tattoo, I have concluded that Kisame is not naturally blessed with them, and that in fact he filed (or had them filed) to sharpness.
His eyes however, are all natural. They do not have a distinct iris, but rather just a white sclera and a dark pupil with a faint markings reminiscent of a star shape surrounding them. It is my opinion that he never blinks.
In the state where he fuses with Samehada, the monstrous aspects of his physiology become even more pronounced, with further gills on his arms, a fin, tail and webbed fingers. These are not seen to be present in his normal form..
In common with the rest of the Akatsuki, Kisame apparently paints his nails - fingers and toes - purple being the chosen colour in his case. He also wears an Akatsuki ring on his left ring finger - it has a yellow stone in its center and carries the inscription "SOUTH"
Normally, Kisame wears the cloak, sandals and leg wrappings of the Akatsuki, with or without the obligatory silly hat, and underneath it appears that like Itachi, he retains the same mode of dress that he would have worn as a member of his previous affiliated organisation. In his case this includes a pair of striped arm-warmers which seem common the other Seven Swordsmen characters. His forehead protector bears the crossed-through mark of Kirigakure, denoting his status as a missing-nin. He wears his in a manner that covers his ears and keeps his hair up and away from his face. It does not seem to interfere with his hearing.
Finally, it is my headcanon that he has a variety of faded scars all over his body and of various levels of severity - while he can heal himself with Samehada, that was not always the case and nor do I think he always resorts to that unless he has to. In addition, he bears the tattoo of a water demon on his right hip. He had this done in Kirigakure, shortly after he became the new bearer of Samehada.
As to what he smells of - mainly leather, metal and a faint whiff of woodsmoke with a hint of tea.
APPEARANCE IN EDENSPHERE: Physically, Kisame will remain the same - he will also retain his scars and the tattoo since they are part of his particular Alternative Universe. He will not, however, have any of his Akatsuki clothing, including the ring. His nails will not be painted purple, and he will have neither his forehead protector nor Samehada Once he goes to seek clothing I expect him to find items similar to what he wore underneath the cloak and will probably favour such items as cargo pants (likely 3/4 length) and loose, jersey upper garments that are easy to move in. I suspect he will be a sneaker or sturdy boots man, and more than likely he will find himself a black scarf to tie around his head to keep his hair up and away from his face. Chances are he'll favour black and grey clothing, and a large, long greatcoat for winter that will be replaced with a duster coat when the weather turns.
Once he finds a big-ass sword (which will never feel quite right to him regardless) he will wear it strapped to his back, out of habit. In fact, he'll start out with a ninjato that he'll also wear strapped to his back, as is the fashion in the Naruverse. You can expect him to have a reasonable array of weaponry as soon as he can - and he will incline mostly towards bladed weapons - swords, knives, and shuriken.
PERSONALITY: In a lot of ways, Kisame is extremely old-fashioned. His beliefs and behaviours are centered around the notion of combat as a gauge of worth and honour. Kirigakure (his home village) appears to have a fiercely militaristic outlook and this is reflected in Kisame's opinions and behaviour as shown in canon - he lives to fight and is never happier than in anticipating or participating in combat with a worthy opponent. He also displays a good deal of single-mindedness - if someone or something gets in the way of what he is doing, he will eliminate it and continue with his mission. If I had to sum him up in a sentence I would call him "a mercenary who enjoys his work".
He's capable of building casual relationships with others - although I'm not sure he would regard them as "friendships" in the usual sense of the word - I'm not sure that's a concept either in his vocabulary or experience. As a missing-nin he's a drifter and casual, passing conversations would have accounted for most of his interactions outside of his partner. In general, Kisame has polite mannerisms and speech. In canon he is considerably less hostile to other members of the Akatsuki than, say, Deidara or Hidan - although he's less habitually courteous than Itachi and seemingly more willing to joke about their life and comrades in the group. For example, Kisame is the only one who expresses sadness at Tobi's supposed death, saying that he'll miss him because he brought some humour to their "gloomy organisation". So it seems that if someone amuses him he is inclined to like and have at the least a surface relationship with them.
Kisame's own sense of humour is displayed throughout his appearances - with Itachi, during action scenes and in the wider Akatsuki sections. I would classify it as "somewhat dark, a bit morbid and often inappropriate", which is much as one might expect from someone who has spent most of their life as an outcast/assassin/mercenary/criminal and most likely dodging other ninja hunting him for the bounty on his head.
Despite his keenness to fight and seemingly antagonistic speech under certain circumstances, Kisame's old-fashioned values show through in how he gravitates most towards those who command his respect through their leadership and combat skills. To these types of people he is loyal and willing to follow orders almost without question. He's one of the few Akatsuki to be consistently respectful to Pein as leader, and he responds to his partner Itachi's tactical orders without apparent question - even when it's likely he realises that his last service to Itachi will REALLY be his last. When Madara reveals himself after Itachi's death and we learn that Madara used to be Mizukage of Kirigakure, Kisame responds that he is reassured to hear that Madara is the one pulling the strings.
This is not to say that Kisame is stupid or not able to operate alone - he rates a 3.5/5 on intelligence in the Naruto databook, which compares favourably with a lot of the cast. Pein certainly trusts him to capture the four-tailed demon alone, and he does so - later Madara sends him to do the same with the eight-tails. He's the only Akatsuki trusted with entirely solo retrieval missions which speaks to both his strength and his ability to conduct a one-on-one fight. In combat, he's prone to impulsiveness to get things started, but he can also exercise restraint when the situation calls for it - enough to test out his opponent in order to assess their powers and abilities. In the same vein, he does not seem eager to attack at full power from the off and keeps his own abilities hidden until the situation requires them. He seems to be a man who knows his limits and recognises other peoples' superior skills - such as long term tactical thinking, in which area he defers to Itachi, Madara or Pein.
I've seen Kisame's general attitude to violence portrayed in a number of ways, from beserker to sadist, but I tend to take a much less extreme view of him based on the few scenes that he has in canon. It's certainly true that he enjoys fighting and demonstrably relishes both the prospect and reality of combat. And it's also true that when he and Itachi are sent to apprehend Naruto - then a young boy - Kisame suggests cutting off his legs so he can't escape, and later cutting off his arms so he can't perform hand seals. However, my view on this is that Kisame is a pragmatist more than a sadist. He's been sent on a mission to a hostile village to achieve an objective, and he wants to get it done and get out without the aggravation of having to chase or fight a kid who has a notoriously powerful nine-tailed demon trapped inside him. He also knows that the kid is going to die anyway when they extract the demon, so it makes no sense to him to worry about the boy's well-being. Ultimately, while he enjoys violence in the course of a fight, and I don't regard him as having any high moral stance on the matter (he makes no move to stop Itachi torturing Sasuke and in fact seems quite comfortable with the idea) I don't think that he is the type to indulge in physical torture for no purpose. I think it's more that he has been conditioned since his early life to be desensitised to violence - what appears perfectly normal to him seems extreme and unnecessary to others. Does he like to kill? Maybe - I certainly think that sometimes he gains a good deal of satisfaction from it. But I think it's more accurate to say that he likes to fight, and regards death simply as an unavoidable outcome of violence.
All that said, at the end of the day Kisame is a criminal from a village that expected friends to kill friends with no mercy in order to graduate ninja school. I don't think of him as a man with a lot of interest in right or wrong, save for his own personal codes. He likes material comforts, and he has no problems with taking money for his work. I believe that he would steal, lie, cheat and kill in order to get by or if he thought it would significantly benefit him in some way and he could get away with it. I also don't think he'd be beyond using "physical persuasion" to get sex if he wanted it badly enough. I liken his morals and general character very much to those of enlisted soldiers in a past age, who could commit atrocities on one day and acts of selfless heroism on the next, and who simply treated it as a job that paid well and that they were good at.
Likewise I think that much like a soldier Kisame can form intense and close relationships with comrades, but that they would be of a vastly different type than what we might expect from modern civilian friendships. In general he will treat such relationships as probably fleeting due to the nature of his own lifestyle and the inevitable fates of those who share it. During his time in Akatsuki he sees the organisation decimated but seemingly accepts this as normal and makes few openly stated regrets. He will look out for and protect his comrades, yes - but only for as long as they are able to do the same for him - should they become a liability to himself or to a mission, I believe that his pragmatism would result in his taking their life to ensure his own. I think in Itachi's case, that point was probably rapidly approaching, based on the probing into Itachi's mental state he conducts in canon. It's almost as if he's testing Itachi's weakness (or lack thereof) repeatedly, and I almost think Kisame demonstrates a sense of relief when the Sasuke/Itachi fight is over and Itachi has been killed. Kisame simply says (paraphrasing) "if he's passed, then I think I'll spread my wings a bit" which gives the impression that he's felt trapped by the situation, since there's never been any indication he resented Itachi as a partner - in fact, unlike most of the rest of the partnerships, the worst we see from those two is banter/glare exchanges. They genuinely seem to respect each other and work well together. I think that by choosing to die at Sasuke's hand when he did, Itachi also removed a decision from Kisame that would have been inevitable, but not one he would necessarily have relished making.
Kisame has his faults - canon demonstrates that he is prone to being cocky and to taunting his opponents (and Itachi, whose marble exterior he seems to make it his mission to chip at, and who seems to take it in his stride). And his personal moral code seems to be offended by anyone who disrespects him, lies to him, or forgets his face/name - the latter probably because he seems to remember almost everyone he fights and especially if they offered a good challenge. Pein also states that Kisame's sole reason for joining Akatsuki was "spite" which indicates that he has a tendency to hold a grudge when wronged.
There is very little examination of his motivation for anything in the manga or the anime and it is not something that is a conversation point for him or Itachi. My personal take on him due to the old-fashioned attitudes as mentioned is that he is constantly seeking a challenge - people who can best him in a fight - and that his ideal death would be in battle, to an opponent who has proved themselves his equal or better. A dishonourable or non-combative death would be anathema to him and I think this is one of the reasons he accepts Itachi's choice so readily and never comments on it negatively - as far as he knows, Itachi is merely choosing the means of his own passing as honourably as he can.
HISTORY: Unfortunately, there is very little information about Kisame's background or history in either the manga or the anime, and nor has he been explored much in the databooks or other fan material. What little is known about him prior to his appearance in the manga as Itachi's partner is vague/sparse/has a nonsense timeline. And even when he is in the story, we get very little from him about his life outside of the immediate mission/battle. For this reason, I have decided to fill in a lot of the blanks with head canon I have attempted to patch together based on canon facts. It is not strictly an AU as the wider Naruto Universe remains unaffected, it is merely a fleshing out and interpretation of the character that I hope will make him a little more rounded (I hope). So pull up a chair, it's story time!
....There was a time in Kirigakure when the young women of the village were often found whispering wide-eyed in corners about what might happen should they dare to engage in sexual relations with one of the many demons inhabiting the Land of Water. In answer, their grandmothers would merely point silently at Kisame Hoshigaki, avoiding speaking his name for fear that the water demons would hear any sound that carried on the mist.
In truth, little is known of Kisame's origins, save that he was found as a baby on the steps of a small, local temple that was known for taking in the orphaned and the unwanted children of the village. There were rumours, of course, of a local shopkeeper's unmarried daughter who died in childbirth only a few weeks before the strange child was abandoned, her baby reported as stillborn but never seen. Her family, naturally, angrily rejected such gossip about any deviance lurking in their otherwise respectable branch of a minor clan and the matter was never pursued.
Whatever the facts of the matter, the child was most certainly real, and having no identifying marks or name the monks chose one for him - Kisame - the word meaning "demon shark", in a literal reflection of his appearance. Kirigakure was not the easiest place for one with such obvious physical differences to grow up. It was a superstitious place, and Kisame's blue skin and hair, inhuman eyes and the gills on his cheeks could not be hidden or disguised. In Kirigakure, merely being born into a clan that was known for its kekkai genkai (inherited jutsu) was enough to mark you out for fear and revulsion - how much worse then, for a child who was rumoured to be the half-spawn of demons.
Fortunately, or perhaps unfortunately, the monks of the temple did not share such beliefs, and they provided for him in the same way that they did for all the other infants in their care. They were not wealthy, and it was by no means a comfortable or caring environment, but he was fed, clothed and received a basic education - at least inasmuch as they were able to teach him, given his tendency to truancy.
Kisame had an unfortunate love of freedom that led him to roam the extent of the village more than was good for him. It also brought him in the way of people who wanted to do him harm - either other children or adults for whom his very existence was considered an aberration. As a result, by the age of six he had already learned when to run and when to fight, and being broader and taller than the other children of his age, could usually make good account of himself when he chose the latter.
It was during one of these fights with the local street urchins that the strange child was spotted by a jounin from the Kirigakure ninja academy. Kisame was almost seven at the time, and impressed by what he had seen, the jounin approached the monks about allowing Kisame to enter the academy as a student. Since adoption was out of the question, and resources were scarce, the monks agreed with alacrity and their most troublesome burden was thus relocated to somewhere far more suited to his temperament.
The jounin's instincts were soon rewarded - Kisame found the lessons at the ninja academy more to his taste than those of the temple, and showed a mastery of both taijutsu and ninjutsu within a short space of time. His skill with a katana was particularly noted, as was his ability to assess and counter any opponent's attack. Bullies swiftly learned to leave him well alone, and the necessity for him to run from any kind of fight became a thing of the past. The stamina that he drew from his unusually high levels of chakra served him well through the stringent and militarised tests of endurance that were common to the Kirigakure academy.
By the age of ten, he had learned all that they could teach him. The harsh graduation ritual of the time demanded that all students of the graduating class be pitted against a classmate in a fight to the death to establish those most fit to move up into the ranks of the village ninja. Any who refused were automatically dismissed - a failure to follow orders or a tendency to show mercy to a weaker opponent both being considered undesirable traits in a shinobi of Kirigakure. Matches were drawn by lots, and unfortunately for Kisame, when his name was called, he found that his opponent was not to be one of the more notorious bullies, but instead an older boy who had generally treated him with kindness. Nevertheless, Kisame's desire to further his skills as a ninja exceeded that of any regret he might have felt, and if his first kill was not the one he would have chosen for himself, it was at least honourable, and he did his opponent the kindness of dispatching him speedily.
Again, his prowess during his graduation had been noted - this time by one of Kirigakure's famed Seven Ninja Swordsmen of the Mist - a loose but exclusive organisation consisting of only the greatest blade-wielding shinobi of their generation that Kirigakure can produce. So it was that Kisame found himself not only a newly qualified genin, but a student of the most feared of the Seven Swordsmen - the wielder of Samehada.
Another five years of study in the techniques of jutsu and the skills of battle followed, and the child Kisame grew into a tall, ungainly teenager with a burning desire to inherit his sensei's legacy and to command the power and respect that came with membership of the Seven Swordsmen. In accordance with their strict traditions, Kisame had his teeth filed to sharpness and chose himself a new name, Hoshigaki - the first family name that he had ever known - to signify his decision to devote himself to the Swordsmen and to Kirigakure for life. It was also in this period that he learned the value of money, and the enjoyment that could be found in such vices as alcohol, gambling and women - although he also learned by painful experience how to moderate his appetites for such things.
At thirteen years of age, Kisame followed the Swordsmen into battle in the Third Great Shinobi World War, earning his promotion to chunin in the field. Afterwards, In company with his sensei, he undertook a number of covert missions for the Mizukage, operating both in the Land of Water and beyond it. For the next few years, Kisame faithfully served his village, conducting numerous missions and unquestioningly carrying out his orders. He also became senpai to Hozuki Suigetsu, who along with his brother Mangetsu hoped to inherit a place in the Seven Swordsmen themselves. Often, he joined Kirigakure secret intelligence squads in the guise of an escort, but in reality under orders to assassinate the other members of the party should there be any danger of either men or information falling into enemy hands. It was not work that Kisame relished - inwardly he rebelled against a system that secretly forced him to operate under false pretences, considering it dishonourable and disliking the fact that both Swordsmen and ninja were treated as nothing more than slaves to be played off against one another by the ruling elite.
Despite Kisame's increasing dissatisfaction with the Mizukage and the political leadership of the village, he remained loyal to Kirigakure - he had little choice - until the day that he received an instruction to assassinate his sensei for treason. Kisame had his doubts, but he also had his orders - and he carried them out to the letter. Eliminating his sensei under the watchful eyes of Yagura, Hoshigaki Kisame became the rightful wielder of the great sword Samehada. However, he could not resist expressing his opinion of the work he was expected to carry out, or his cynicism about the integrity of the leadership.
When Uchiha Madara, a legendary ninja from Konohagakure, stepped out of the shadows behind Yagura to reveal himself as the one who had been controlling events all along, Kisame's first instinct was to kill him. But Madara was charismatic, and Kisame and the other Swordsmens' respect for Yagura had dwindled almost to nothing during his rule. The Land of Water was not the most stable of countries, and Kirigakure not the most stable of villages. Thus, when the rumours had begun that Yagura was being manipulated by an unknown power; that he would betray his village and leave it to be ravaged by the three-tailed demon for which he was the vessel, they were swift to take hold. In reality, it was Madara who was controlling Yagura, and Kisame was one of the very few to be shown the truth. But to him, this was merely proof of Yagura's weakness.
Madara outlined his Moon's Eye Plan, and despite any cynicism that Kisame may have privately harboured, he was impressed by the Uchiha's ambition. In return for Kisame's loyalty Madara promised him what he most wanted - freedom and a world without lies. He accepted the offer, and that same day he was acknowledged by the other Six Swordsmen as the Monster of the Hidden Mist. From that day since, Samehada has never left his side.
Shortly afterwards, Kisame began removng key political figures under Madara's orders - successfully assassinating the daimyo of the neighbouring Land of Waves, in a bid to cut destabilise that country and cut off off any interference in the affairs of the Land of Water. He followed that with a number of other similar exploits, all while outwardly still faithfully serving Yagura.
Unfortunately, elements of the plot was brought to light through the diligence of Kirigakure's ANBU by the other leaders of the village. Madara's involvement was not discovered, but the Seven Swordsmen fell under suspicion of treachery. Despite the fact that Kisame believed that the actions he had taken for Madara would ultimately have been for the good of both Kirigakure and the world, he found himself named a traitor and threatened with torture and death. He left the Land of Water, as did the others who had escaped the daimyo's men, with nothing more than Samehada and the clothes on his back. He carved a strike through the forehead protector that bore the mark of Kirigakure and swore that he would never return unless it was to reduce the place to rubble. To this day, he has been true to his word.
For a while Kisame wandered across the mainland, living off whatever he could steal from the bodies of any fellow travellers or bounty hunters unfortunate enough to encounter him. For the most part, he confined his travels to the more unstable countries that skirted the Land of Fire, until eventually he found himself in Amegakure. There, Kisame was approached by Pein to join the ranks of a criminal organisation named Akatsuki - secretly under the control of his old mentor, Uchiha Madara, though Kisame was unaware of this at the time. Making the decision to seal his new status as a criminal and a missing-nin, Kisame accepted and donned the robe and ring that marked him out as a member. As well as finding Pein to be a convincing and decisive leader, Kisame quicky recognised that the Akatsuki's goals would offer him stability, and an opportunity to take the skills he had learned in Kirigakure and eventually turn them against it.
Kisame had mixed feelings about his new comrades, but his respect for Pein as a leader cemented his place in their ranks, as did his ownership of Samehada and his acknowledged skill in battle. Still, it was with some cynicism that he received the order to form a two-man unit with the newest recruit, Uchiha Itachi. Itachi was only thirteen, and had joined the Akatsuki after slaughtering his entire clan in what he claimed to have been a test of his skills. Despite this, Kisame found Itachi distant, withdrawn and difficult to like, and the factor of their difference in age was another cause for resentment. The Seven Swordsmen had been a loosely affiliated group, rarely acting together, and Kisame was unused to the notion of a working with a partner in any sense. However, any doubts he may have had about the boy were banished within a matter of weeks, when Itachi proved himself by slicing off the hand of one of the older members, Orochimaru, after the latter attempted to take over his body. Orochimaru was banished for his actions, and Kisame was impressed by Itachi's decisive response to the attempt on his life.
The partnership proved to be a better one than either anticipated, and as time passed Kisame developed a loyalty and respect for Itachi that bordered on friendship. Their skills complemented each other, as did their temperaments - Itachi's marble demeanour offset by Kisame's tendency to devour life with relish. Together they carried out a number of missions for Akatsuki over the seven years in which they were partners, including a failed attempt to capture Uzimake Naruto, and a more successful one in which they used body doubles infused with their own chakra to repel the ninja of Konoha from an Akatsuki stronghold. In the course of both these missions, Kisame encountered and fought Maito Gai, a ninja who has earned Kisame's enmity through his initial surprise attack and his subsequent inability to remember Kisame's name.
Shortly after Kisame had been despatched by Pein to successfully capture the four-tailed demon, Itachi's younger brother, Sasuke, sought him out in revenge for murdering their clan. At Itachi's request, Kisame stood guard over the appointed meeting place, under instruction not to allow any of Sasuke's team to pass save for Sasuke himself. He followed Itachi's orders to the letter, even when finding Hozuki Suigetsu among the party. Recognising each other from Kirigakure, the two of them fought, until another member of the Akatsuki - Zetsu - interrupted them with the news of Itachi's death.
Kisame did not grieve for his partner, but nor did he seek another, instead preferring to continue on as a one-man unit within Akatsuki. He had no liking for Sasuke, who had been rescued unconscious from the scene of his fight with Itachi by the Akatsuki member known as Tobi. Tobo later revealed himself to both Sasuke and Kisame as Uchiha Madara, the man who had commanded Kisame's loyalty in Kirigakure. With the members of the Akatsuki dwindling, Kisame was reassured to find that Madara was the guiding hand behind the organisation, and his loyalty soon shifted from Pein to Madara. When Pein later sacrificed his own life to save those he was supposed to destroy, Kisame's belief that Madara was a more fitting leader was reinforced. Consequently, when Sasuke and his team failed to capture the eight-tailed demon for Akatsuki and Madara asked Kisame to undertake the mission instead, he accepted without question, and with a considerable amount of anticipation. After all, Madara knew him better than anyone else, and this might turn out to be the fight of his life....
(For canon verification purposes, the actual facts in the above can be found on Narutopedia. The rest is of my own creation. The timeline in places is deliberately vague as that of the canon source is notoriously contradictory).
ABILITIES: Kisame has earned the epithet "Tailed Beast without a Tail" due to his enormous amounts of chakra and his fighting abilities. In Naruto, the Tailed Beasts are demons who wield highly destructive powers and even despite being sealed inside humans, if unleashed are capable of destroying entire villages. They act almost as "ultimate deterrents" in terms of discouraging villages from attacking each other. For a regular ninja to be compared favourably to one in terms of strength and ability should give an idea of exactly how powerful Kisame is. When Kisame appears on his own - fighting Team Gai and cockblocking Team Snake - members of both parties comment on his massive chakra signal, but when he appears in Konoha with Itachi, no-one seems to notice. I conclude from this that he does not have the ability to disguise his chakra signal, and that task probably fell to Itachi.
Chakra - Kisame seems to have huge amounts of chakra (energy) and in that regard is openly compared to series protagonist and vessel for the Nine-Tailed Demon Fox, Naruto, when Kisame is only manifesting with 30% of his usual chakra. Because of what is revealed later in the manga about the nature of Samehada and its preference for its bearers to be themselves powerful chakra users, I believe that Kisame naturally and consistently has a large store of chakra - seemingly to the level of at least a Seven-Tailed Demon. It is not mentioned directly in the manga, but I assume that Kisame's chakra can be drained or damaged by sustained combat/magical means, but that he suffers this at a slower rate than others and recovers faster. I have concluded this from a scene after he single-handedly captures the vessel of the Four-Tailed Demon, stating to Itachi that it was a difficult fight and that he is "a little tired".
General Fighting Ability - In the Naruto databook, Kisame is listed as possessing a 5/5, 4/5, 5/5 in terms of his levels of strength, speed and stamina respectively when compared to other characters in the series. This puts him almost on a level with Might Guy. He also scores highly (4.5/5) in Taijutsu (hand to hand combat).
Other - Kisame is demonstrated as being able to travel underwater quickly and without the need to come up for air in any great frequency. In its basic form, this does not seem to be linked to any special use of jutsu, so I have assumed that the ability is inherent and is related to the gills he bears on his face and shoulders - much like a shark, however, he seems to have to keep moving in order to remain submerged.
Over the years he must have acquired a set of skills centered around such things as first aid and field survival techniques. This would make sense for any missing-nin with a dangerous, covert, and criminal lifestyle.
For the same reason I think it likely that Kisame has the ability to perform basic, low-level chakra healing, of the type that would be enough to patch himself up in the event of physical injury. In fact, I tend to think that all the Akatsuki would have basic training in such techniques given their tendency to wander in remote places without medics and the fact that they can't just walk into a hospital and ask for help. And since Kisame has a LOT of chakra to spare it makes especial sense for him to have that skill and perhaps even to be able to use it on others in a pinch.
Finally, given the fact that he is clearly intended to resemble a shark and the fact that he seems to be very swift to sense and react to personal danger, I think it's also possible that he has a higher than normal sense of smell and keen hearing.
Samehada - Samehada is Kisame's enormous sword, which is said to be the most terrifying of the large and unique swords carried by the Seven Swordsmen of the Mist. Although he is no longer affiliated with Kirigakure, he still carries the sword, which implies that such weapons either have to be earned in combat or inherited. Generally, Kisame wears Samehada strapped to his back with a thick leather strap, and its "blade" is wrapped in bandages. In this state, it appears to be able to unbind and bind its own bandages if a fight occurs, and is also shown to be incredibly heavy such that if slammed down onto the ground by Kisame it can crack concrete or cause a minor, localised earth tremor.
Samehada is not a normal sword in that it does not have a cutting blade. Instead, it is covered in sharp scales that "shave" the skin off opponents. Its handle is shown to have hidden spikes that protrude and cause injury if anyone other than its normal/preferred wielder attempts to use it. Kisame can partitally fuse with Samehada in order to replenish his chakra or heal himself, and in addition, using Kisame's chakra, Samehada has the ability to absorb an enemy's chakra and transfer it to its wielder. In this manner, the more powerful the opponent, the more powerful Kisame becomes. It is unclear whether Samehada must be making contact either with the body or weapon of the opponent in order to drain their chakra - personally I say yes, it does. It should be noted that Samehada's ability in this regard appears to be limitless - it has no difficulty absorbing Naruto's entire chakra, for example.
Finally, and most mind-bogglingly, Kisame possesses the ability to completely "fuse" with Samehada and transform himself into a "real" monster in order to increase his lethal fighting power. Unfortunately we don't see a great deal of what he is capable of in this incarnation but I laughingly call it his "Incredible Hulk" power ( mean, WTF, Kishimoto?). Anyway, the fused state *does* appear to give him an enhanced ability to use water jutsu and to breathe underwater without being in constant motion. Perhaps this is related to the additional gills on his arms and body.
Additional head-canon about Samehada: In general the Akatsuki members in Naruto appear to be paired into teams that balance each other and that are not susceptible to each others powers. Because of this, I have guessed that as well as being "hard to kill" and able to damage Itachi by draining his chakra, Kisame also likely possesses some protection against the genjutsu (mind control) associated with Itachi's mangekyou sharingan. I tend to link this to Samehada, and have theorised that Kisame can use the sword to achieve the effects that Naruto is taught to escape sharingan - including reversing or stopping the flow of his chakra. Based on references to how Samehada responds to powerful chakra in canon, I also consider it possible it is able to "sense" the use of genjutsu or indeed any ninjutsu that either utlises or interferes with the normal flow of chakra.
Ninjutsu - Ninjutsu is the moulding and manifesting of chakra to use it as a weapon or defence in combat. Generally speaking, jutsu are linked to the elements and Kisame's jutsu involves earth and water techniques. Most jutsu users manipulate the chakra using hand movements (called "seals"). He is rated in the databook as having a levelof 4.5/5 for ninjutsu use and 3.5/5 for his proficiency and speed with hand seals.
List of his canon-demonstrated jutsus:
1. Earth Release: Underground Submarine Voyage - Kisame can sink down into the earth and travel through it below ground as if it were water.
2. Water Clone Technique: Kisame can create clones of himself out of water to confuse the enemy. Clones have 1/10 of the users power and can only operate at close range to the original. Considering that Kisame is reasonably powerful, you can assume his clones are too. I assume he needs to have water available to create clones. If damaged, the clones revert to water.
3. Water Prison Technique: Kisame or his clones can can trap his opponents in a spinning ball of water which is virtually inescapable. He (or a clone) has to keep an arm inside the ball at all times to sustain it, and it requires a body of water to be available.
4. Water Release: Exploding Water Colliding Wave - Kisame can create and spit out a ridiculously large body of water from his mouth. This can form a "tidal wave" that he can ride, but which can sweep away his opponents. He also seems to be able to manipulate the flow of the water to create towers or geysers while using this technique.
5. Water Release: Great Exploding Water Colliding Wave - same as 4, only that Kisame retains control of the water once it is released and forms it into a giant orb.
6. Water Release: Five Feeding Sharks - By placing a hand into a body of water, Kisame can release a water shark from each fingertip that will attack an opponent consecutively. The opponent must be in the water for this to be effective.
7. Water Release: Water Shark Missile Technique - Kisame can form a large shark out of water and force it to attack an opponent.
8. Water Prison Shark Dance Technique - this can only be achieved after using 5 and fusing with Samehada. Basically, Kisame becomes the centre of the orb of water and can move it around to prevent his opponent escaping. Ultimately they will suffocate, while Kisame's enhanced ability to breathe underwater means he remains unaffected.
Genjutsu - Genjutsu is a method of disrupting the chakra in an opponent's brain in order to create illusions. Kisame is rated as having a level of 2.5/5 in this skill, although it is never shown to be demonstrated by him in either the manga or anime. Because the nature of his jutsu is water and earth based, I would theorise that his abilities in this area probably centre around such things as causing an opponent to believe they are drowning or suffocating. Given his moderate ability level and his demonstrated preference for physical combat, I would imagine genjutsu would only be used by him as a distraction technique.