I feel like I missed as to why he committed suicide. Like I get that him and Mafuyu had an...

i still think that it wasnt on purpouse
i mean who nowdays thinks they could actually did from achocol intoxication, so i suppouse he was drinking away his sorrow and thats how it happend
bad timing and partly mafuyu's fault but also his

When they had a fight, mafuyu said "can you die for me then?", maybe when yuki was drunk he remembered that and then commit suicide. He wanted to tell mafuyu that he can die for him.

like commented above, while having their big argument, mafuyu asked him he he could die for him out of anger (since he said he couldn't live without mafuyu)
then he got really drunk, for the very first time-
this was probably just something repeating in his head, and mafuyu being the only person who's truly been there for him from the very beginning, he was totally heart broken (i'm pretty sure he actually hung himself tho, not died from intoxication)

Yeah I think he hung himself too, which is the reason I thought it was too extreme an action to do just because someone said "would you die for me". (Overdose would make more sense) But we dont know much about his character except that he loved Music and Mafuyu and was social. He might have been suicidal or something, which I think would give more purpose to his actions! Idk I think I'm over thinking it, but its a topic not seen in Anime/ media a lot -Moving on from a past love- especially one who is dead. So I hope it stays relavent to the plot instead of just casted aside.

sdfkzjnf yeah, i was thinking that he was probably previously depressed or maybe even thinking about suicide before their argument, which would fit in with mafuyu's friend saying he wanted to be forgiven for knowing something ?
hmm, about it being cast aside- i'm not sure if it'll be something big-big, but it does play a part in mafuyu's music/character