an impulsive murder - muu's suicide ideation in after pain
I find it interesting that Muu mentions "if [Rei] wasn't here", using the exact wording as the opening of After Pain (いなくなれば, "if I wasn't here") - noting that 消えばよかったの "it would be better if I disappeared" follows right after
This makes me think that Muu was suicidal during the events of After Pain - likely unable to cope with suddenly being targeted and not having any clear reason why, she has no choice other than to interpret it as a personal fault. It's a vague personal fault that she tries to make up for and seems to blame herself over, seeing as she continues to give gifts to her bullies in hopes of 'fixing' things. She continuously tries to make things right and apologies for her own existence without even really knowing what she did wrong in the first place:
We also have mention of a suicide note:
Calling it a 'counterattack' implies that she saw suicide (and therefore the burden of guilt/responsibility) as a means to actively get back at a tormentor - and based off her continued efforts to befriend her bullies, considering them "normal friends" (T3Q9) and of course this question, it's Rei she's thinking of. She also implicitly directs the following to Rei:
Based on what we know about Muu's situation in Pain, to me it sounds like she wants to threaten Rei with her own suicide in order to finally get some sort of approval "I love YOU" from her - which would either 'undo' all the bullying and put Muu back on top, or otherwise confirm that Rei would be torn up by Muu's suicide and that her own revenge would be successful.
Obviously, it's not how it goes. Instead of apologising, trying to make anything right, or even visibly showing guilt over Muu getting bullied as a result of her actions, Rei rebuffs her:
I think what she's willing to accept is "[her] fault" is Rei's murder - deep down, she probably knew that she didn't actually do anything to deserve bullying and therefore doesn't need to commit suicide - she wants to be "alive" and asks if she can "breathe" and finally get respite from the torment.
She suddenly finds herself in the position where rather than the world being a better place if Muu wasn't around (いなくなれば), it was Rei who indirectly caused the bullying and should disappear (消えばよかったの). Her own suicide in front of Rei (or at least likely acts of self-harm, given she was carrying a razor) didn't go to plan even when she very much is deserving of pity.
Therefore - if Muu didn't actually do anything wrong to deserve getting bullied, then she doesn't actually 'need' to harbour suicidal intent. If there's anyone who should die, shouldn't it be the person who attacked her first?
Interestingly, Muu's been depicted missing a shoe a few times - a distinction she shares with 0607's placeholder victims in Undercover, both victims of suicide.
