Assumptions and etc. made from canon...
PERSONALITY: GYNOPHOBIA
Heine also suffers from gynophobia, most likely due to the events where he killed Lily (it's heavily implied but never directly stated in canon if this is the reason, it may also have to do with his "mother", Angelika Einsturzen). The "severity" seems to vary depending on the female in question, ranging from being so nervous at the thought of coming in contact with them (in one instance, he is with Badou and Kiri, the owner of the place, comes up beside Heine's seat and he slides his chair over to practically sit himself on top of Badou) to nothing at all (Nill is the only female he can touch and be touched by without it sending him into some sort of panic, although he is shown to be able touch Naoto on some level as well... even if he does drop her to the ground after catching her fall in the end. Regardless, he has shown little issue being within close proximity of her, able to fight alongside her and have conversations at close distances.). **To be honest, I'm not sure if this variation is because his gynophobia is special circumstance and more selective than we are originally intended to believe or if the author simply can't make up his mind. I usually play him as being fine with females unless they invade personal space or he has to touch them.**
Kiri might resemble Einsturzen due to her age and nature of being kind. While Einsturzen and Kiri act nothing alike, Einsturzen seems to have always used very affectionate words and physical care (hugs, etc.) with Heine while basically speak words the exact opposite of what her body language suggests. Since he doesn't know Kiri and actually almost slams Badou and himself off their chairs in sliding quickly away from her when he stands next to her, it's fair to say something triggers in him when he's within reaching distance.
Naoto probably would resemble Fruhling, and his standoffish bitchy nature may suggest his feelings towards the "caretaker". Fruhling is very independent and capable and not really one to take any shit. It's pretty easy to assume Heine with his personality would butt heads with such authority and Naoto is very headstrong and engages with him in bickering. I just think Naoto's presence/katana/qualities unconsciously remind him of Fruhling/what Fruhling basically represented while he was in the Underground (maybe restraint and inability to escape, not to mention possible abductor if reaching for straws with Naoto's background story, who knows...).
Nill is obviously a reminder of Lily. Someone he couldn't protect/was the big brother figure of. Judging by Chapter 52, Heine seemed to keep the balance/piece and "take care" of his two siblings during all this. He seems more confident and in control than either of them, but he's also the one who in the end who rips them apart. Considering we see Heine as very uncaring about others (even children, as seen in an early mission with Badou, he just does what he does and saves them because it's a job, no real concern for them like a general person may be for a little kid being a victim to kidnapping.
Noki and Luki are actually the... last set of female influence in his life, and he has no issues whatsoever with touching them and breaking them in half if they get too annoying. So, since it's so unclear, with all this in mind, I usually play him with a slightly different mindset. He's "afraid" of women in general because, let's face it, every single person that has made him helpless or miserable or a monster he doesn't want to be are all women. Men are nonexistent in his situation, it seems so far, until Bishop picks him up off the street and takes him in. With Heine how he was and how he is now, I don't feel he has a problem with women in general so much as women have made very VERY distinct influences on his traumatizing past. He might feel he can't trust them or something, but I guess I assume it like this:
He's afraid of women that can trigger a reminder of Einsturzen. She is, afterall, the one who had complete control over him and fucked everything up. It's really because of her he ended up killing Lily. Funnily enough, as gruesome as Einsturzen is in morales and purpose, she is extremely gentle and motherly in both appearance and choice of words with him. Thus, someone like Kiri, a woman who would probably be fair to say could be in Einsturzen's physical age range who is kind and good natured to people but has a bossy side, too (with Mihai), probably is what makes him freak out when she gets near him. He can't help it, Einsturzen always seemed to do her worst damage by being close and caring to him (hugging him, being a motherly figure, whatever. )
He hates women who have a sense of "power"/"authority" like Fruhling. If we assume from Naoto's story that Heine was picked up off the streets the same way/by the same person as who killed her family and left her to die, it's fair to say he loathes Fruhling for bringing him there in the first place and being able to "keep" him there. It's resentment, it's pretty typical even when bad things don't happen with people who don't want to be controlled, and Heine even has pretty good reasons to add to his already "fuck you i do what i want" nature. His personality is slowly starting to change towards Naoto the better they get to know each other and the more he starts to... uh, see she's not quite as "in charge" of things as she initially comes off as in their initial meeting (she has a lot of nerve to be stalking him around and expect to get information out of him, afterall... he's not anyone's dog, but it's possible that Fruhling was able to get him to be and thus there's a lot of hate and resentment for someone oddly familiar just coming into his life randomly all demanding to give information he hasn't told her before. So, he's naturally irritated from the start and while is aware she isn't Fruhling and probably hasn't/will never make a connection to the two, he's unconsciously defensive towards anyone who even reminds him of what could have been part of his life back in the Underground.
Same concept as someone getting automatically defensive when asked a question about their actions that *could* lead to a situation they've experienced once or many times before that they dislike. It's the preemptive strike to try and intimidate others off that possible track. Think twice. It's not the person asking the question's fault or any fear/wariness of the person themselves asking the question so much as it is over the situation that could develop from there.
With Nill and Lily, I don't think Lily made him so much afraid of women as much as feeling like he wasn't able to protect her. He holds a lot of guilt for the situation, but it's at this point hard to say that just killing her is the sole reason. (In Chapter 52, it's seen he and Giovanni are on relatively good turns as well, he looks out for both of them and is harsh with Giovanni, but protects him from Lily when she goes crazy and tries to choke him.) He's the big brother, the protector, and an earlier flashback of his past in the Underground has a Lily who was just moments ago berserk and ripping a monster into pieces scared and unsure of what was happening and crying on him and clinging for support. Lily is obviously crazy and she's telling Heine she's scared and seeking comfort. Giovanni when they were all younger was very timid and unsure of himself, always doing things that could get him killed. Both of them are unable to protect themselves (or protect others from themselves such as with lily unable to keep her dog personality in check) and Heine's the one they're depending on to do it for them. And Heine is for a while. He seems the most stable and confident and quite in control of his berserker mode (or resistant to it affecting him negatively, maybe) and he's the one who keeps them in check. Actually, for whatever reason, Lily seems to be able to regain control of herself because of Heine. Now, one day they're all pitted against each other and, well, if Heine was as we see him in Chapter 52, it's safe to say that he would have been able to potentially stop a carnage between the three of them. For whatever reason, though, he snaps. And suddenly, when he comes to his senses, he's ripped his sister to pieces and severely injured Giovanni. It's the first time he loses control, it seems, and unlike Lily there's no one to calm him. And his one mistake ruins everything he was protecting/looking out for. It's not even failure to help at a point, it's more likely the realization that the dog isn't something he can control and he's just like Lily was. He's powerless and not only can he no longer protect those who look to him like he has the ability, but he's the one who ends up killing them both. The one who was in control, the protector, the one keeping them all alive despite.
Yeah, that's a little shitty to come to terms with. With Nill, he might simply be afraid of her touching him at first because of what he did to Lily, but when he realizes he has control around her and can interact with her without flipping his shit, he becomes quite protective and brotherly to her. She's almost like a second chance to put himself in denial about the existence of the monster inside him. She's not a trigger concerning his past, she's a comfort and gives him a little bit of purpose again. However, unlike with Lily and Giovanni, he mostly protects Nill by making sure she is safe away from everything. He puts trust into others to protect her perhaps more than he does himself, often leaving her with Bishop while he goes about business and even letting Naoto take on the active protector role (perhaps trusts her stability more than his own in a high tension situation.)
Finally, Noki and Luki are pretty much just representative of the rest of his opinion towards people. Doesn't care, doesn't want to be bothered, and christ if you keep busting his balls he just might turn around snap your neck. Same concept as someone getting automatically defensive when asked a question about their actions that *could* lead to a situation they've experienced once or many times before that they dislike. It's the preemptive strike to try and intimidate others off that possible track. Think twice. It's not the person asking the question's fault or any fear/wariness of the person themselves asking the question so much as it is over the situation that could develop from there.
With Nill and Lily, I don't think Lily made him so much afraid of women as much as feeling like he wasn't able to protect her. He holds a lot of guilt for the situation, but it's at this point hard to say that just killing her is the sole reason. (In Chapter 52, it's seen he and Giovanni are on relatively good turns as well, he looks out for both of them and is harsh with Giovanni, but protects him from Lily when she goes crazy and tries to choke him.) He's the big brother, the protector, and an earlier flashback of his past in the Underground has a Lily who was just moments ago berserk and ripping a monster into pieces scared and unsure of what was happening and crying on him and clinging for support. Lily is obviously crazy and she's telling Heine she's scared and seeking comfort. Giovanni when they were all younger was very timid and unsure of himself, always doing things that could get him killed. Both of them are unable to protect themselves (or protect others from themselves such as with lily unable to keep her dog personality in check) and Heine's the one they're depending on to do it for them. And Heine is for a while. He seems the most stable and confident and quite in control of his berserker mode (or resistant to it affecting him negatively, maybe) and he's the one who keeps them in check. Actually, for whatever reason, Lily seems to be able to regain control of herself because of Heine. Now, one day they're all pitted against each other and, well, if Heine was as we see him in Chapter 52, it's safe to say that he would have been able to potentially stop a carnage between the three of them. For whatever reason, though, he snaps. And suddenly, when he comes to his senses, he's ripped his sister to pieces and severely injured Giovanni. It's the first time he loses control, it seems, and unlike Lily there's no one to calm him. And his one mistake ruins everything he was protecting/looking out for. It's not even failure to help at a point, it's more likely the realization that the dog isn't something he can control and he's just like Lily was. He's powerless and not only can he no longer protect those who look to him like he has the ability, but he's the one who ends up killing them both. The one who was in control, the protector, the one keeping them all alive despite.
Yeah, that's a little shitty to come to terms with. With Nill, he might simply be afraid of her touching him at first because of what he did to Lily, but when he realizes he has control around her and can interact with her without flipping his shit, he becomes quite protective and brotherly to her. She's almost like a second chance to put himself in denial about the existence of the monster inside him. She's not a trigger concerning his past, she's a comfort and gives him a little bit of purpose again. However, unlike with Lily and Giovanni, he mostly protects Nill by making sure she is safe away from everything. He puts trust into others to protect her perhaps more than he does himself, often leaving her with Bishop while he goes about business and even letting Naoto take on the active protector role (perhaps trusts her stability more than his own in a high tension situation.)
Finally, Noki and Luki are pretty much just representative of the rest of his opinion towards people. Doesn't care, doesn't want to be bothered, and christ if you keep busting his balls he just might turn around snap your neck.