May I request some Hairu headcanons?
you may!! and, i apologize for being so late to this. thank you so much for the ask. hairu is not a character i'm 100% confident in my analysis of & ability to create in-character headcanons for, so i will try my very best. feel free to disagree with anything i may list!!
hairu really likes melon bread. this is something we know about her. that being said, i think that she once attempted to make her own. a strong, sort of related, headcanon i have is that a lot of the sunlit garden kids are not..... the best at cooking. i don't think they were ever taught how to do it because they had distinct and clear purposes based off of species, that did not include knowing how to cook. i think hairu's kitchenette looked like a warzone post-melon-bread-making. the bread came out both burnt in some places and raw in others. she found the end result very discouraging and had to take an hour or two to sulk before she could muster up the will to start cleaning up her mess. she definitely sent ui pictures of the poorly cooked bread, and the mess of her kitchen.
i view her and saiko as being friends. not super close friends, but friends. there's some sort of social barrier between the two of them that prevents them from ever having deep conversations. hairu is too used to being around older people and the hyper-maturity required by the CCG when addressing serious topics, as well as her feelings about her upbringing having to be stifled. saiko is too used to shielding herself from feeling her negative feelings about her life and the world around her with humor. that's not to say their friendship holds no depth, though. most of their conversations take place over text, and are usually started by one sending a photo or video. the photos and videos are frequently something like a meme, or an unflattering photo of a colleague, or a video of something humorous happening around the chateau or CCG building. but, sometimes, it's a something one of the girls sent to each other with the caption "this reminded me of you." these are the moments when the depths of their friendship are displayed. these can be anything from a stuffed animal, or a flower, or some food, or an animal, etc. for saiko they are usually blue and for hairu they are usually pink.
hairu is canonically the only woman investigator who wears pants. i think that she explicitly despises skirts and dresses. she doesn't even wear them for formal events, she wears a pantsuit. i think it's in part a personal comfort thing, and also a protest against the expectations put on her. skirts aren't required, but as an investigator who is a woman, you get a lot of dirty looks for not following something that "isn't required." the looks have never bothered her because she's certain of who she is and what power she holds, she's honestly sort of cocky. she likes how her cockiness and confidence in her abilities makes men in their field uncomfortable. her personal style is still pretty feminine, just she only wears pants and shorts as bottoms.
she has a tendency to bite her nails when deep in focus. like, when she's typing up a report or reading through a file. hairu also kind of sits weird at her desk when focusing too, she sort of slouches and has her left leg bent up with her heel resting on the edge of her chair. when reading, her left arm hugs her bent knee, but when she's typing, it's outstretched. to combat the nail-biting, she puts clear polish on them. the slouchy posture makes her back hurt sometimes, so to combat that she wears a compression(?) garment to give more posture support when she's in for any length of time at her desk/computer.
this one is super random, but i think that if she weren't born into the sunlit garden and never had to become an investigator (or if this was an AU with no ghouls at all), she would be a surgeon. i'm not too sure of what field she'd use her skills for, but i can definitely see surgery as something she'd want to do. i kinda feel like hairu is someone who has a great appreciation for human anatomy and the way bodily systems function. going back to just her canon positioning in the story, i headcanon that anatomy and physiology is something she was very interested in when she was younger. perhaps i am saying she is autistic and it's a special interest she's had since childhood. no one really knows of this part of her, she usually packs it away very deeply. the only real time it's displayed is when someone says something that sort of makes her ears perk up and triggers an, often times morbid, tangent about the human or ghoul body. most find it off-putting, but there's a real sparkle in her eye when she's explaining these things that's undeniable.
hairu has the opposite of a green thumb. she can accidentally kill any plant, no matter how difficult it's supposed to be to do so. though i think she's in complete denial of it. like, deep down she knows this about herself, but she finds herself buying a new plant here and there because "this one will be different." her denial sometimes extends to her even keeping the dead plants around because she thinks she can possibly rejuvenate them. subconsciously, she perhaps projects her own feelings onto the plants. the plants represent her hope to attain a life not laid out by her birth, and her care of the plant is how she does all she can to nurture it, but it just ends up dying anyways, kinda like how her daydreaming of a different life always gets shot down when the reality of her situation sets in. idk.
obligatory sexuality and gender headcanon: i view her as being bi with a preference for men, and also somewhere on the aromantic spectrum. perhaps cupioromantic? orrr bellusromantic? idk i saw this post a while ago and really liked those labels for her. as for her gender, i think she identifies as a cis girl but the TV Might Be Glowing if you know what i mean. she kinda has the mindset of that one tweet that's like "i'm probably nonbinary but i have a job so idrc about that rn." she sort of enjoys the idea of all pronouns being used for herself but she isn't sure of how she can communicate it with others. it feels forbidden to her due to her birthplace & upbringing. i also think she would make an excellent drag king, and she sort of watches videos of drag kings when alone at her apartment Thinking about how she wishes she could do that.
i hope these were good!! <333