Responses
There have already been various hints on what happened...
My bet is tsukasa was hurting him, (which hanako forgave originally) but then it got worse and he started hurting other people and killing/torturing small animals and insects until hanako couldn't take it any longer?
Something like that probably
Agree. I think he tortured Hanako too much, so he just snapped one time(bcs Tsukasa said that he loves to see people snapping and unrestrained, just like Hanako when he killed him)
I love this so much, but I hope after this arc (the 7 school mystery are now complete) author-san will expound on Hanako’s past (what really happened? Why he killed tsukasa?) and how will Yashiro die?