Hello!! I meant to respond to your reply but I forgor -- thus, I'm here to ask about any Mahiru thoughts/theories/opinions you have 👀🌻 (only if you want, I'd just love to hear!)
OHHH you have no idea how happy i am to talk about mahiru... she is so dear to my heart. as evidenced by the last time someone asked me about her and i accidentally wrote a 1900 word response. going to try and make my answer to this ask a little shorter lol.
i think there's just something really compelling to me about the fact that like. whatever it is that happens with her boyfriend feels so much more like an interpersonal problem that went horribly wrong than like a murder case. obviously the characters with more traditional and direct murders can be and are interesting as well but there's just that special flavor of tragedy to the instances where characters never intended for their "victim" to die. especially mahiru, who sincerely loved her boyfriend and seems to have not even wanted to inflict Any sort of harm nor to have been aware that she was doing so.
i really really like and resonate with how she deals with the realization that she in fact Did hurt her boyfriend though. it's just so nuanced and realistic, you know? she blames herself for her emotions and desires and her inability to get it right, and she doesn't want to hurt anyone again... but she also can't stand the idea that she'd have to be alone and unloved for the rest of her life in order not to hurt anyone, either. which i think is a dichotomy mahiru seems really familiar with: she doesn't really want to get upset with her boyfriend or hurt him or anything like that; it's just that she also desperately wants more attention and love and commitment than what she's getting (and ends up giving in to that desire and demanding it seemingly to his detriment, judging by all that "calling you in the middle of the night" she mentions in this is how to be in love with you, or the "if you don't hug me our hearts will drift apart").
which is... a really realistic struggle, you know? wanting something from someone that they for whatever reason can't give you. on one level i think she does need to work on how to actually be okay by herself, and to find healthier outlets to cope with it. on one level her behavior is destructive and harmful to others. but on another level, she's not wrong for having a high desire for attention and reassurance, either. and it seems like she doesn't really know how to deal with those emotions. or with her emotions in general, actually... she gets carried away with happiness when things are good, and sinks into despair when they're bad, and doesn't know how to handle it or find a middle ground.
it's just a really nuanced situation without a clear right or wrong, and that level of difficulty in coping with/controlling your emotions is really hard to handle even without a situation where you end up becoming implicated in your boyfriend's death... i feel for her a lot :( poor girl just needs therapy and a better support system in her life. and actually circling back then to my tags on your fic... i think in another world, that mahiru with her uncontrollable emotions and ideals of love as her meaning to live could absolutely find some sort of kinship and seeing herself in kotoko, who similarly seems to struggle with her anger towards injustice spiraling out of her control and with her vigilante work being connected to a sense of purpose for her.
unfortunately, as is... i think the opportunity's been a bit lost with mahiru's canon guilty vote and what happened between them. mahiru forgives her, yeah, but... i just don't think it'd be great for her to pursue a connection with someone who nearly killed her.
that's what alternate universes are for though, right? ;)