okay but does anyone know what’s up with hanako’s brother... like... what exactly is h...

I guess he still holds a grudge of Hanako killing him? Not entirely sure yet but I guess we’ll look into it in the future

There are several theories about him. Some people are speculating that Tsukasa might be Hanako's Yorishiro because of the black seal on his cheek that looks similar to the seals on the other mystery's yorishiro. But that theory doesnt make full sense to me because when they had their reunion, Hanako seemed a bit shocked to see his brother. But at the same time maybe Hanako sealed him away somewhere and wasnt expecting to see him again, because technically those seals like the white one Hanako has are meant to stifle powers. And if I remember correctly Hanako was unsuccessfully exorcised by Kou's grandmother??? So that might explain the white seal on Hanako. Perhaps Hanako tried using the same method on Tsukasa? Orrrrr perhaps the evil spirit Kou mentioned his grandmother was trying to exorcise was actually Tsukasa and not Hanako. And because they are twins its to be expected that Kou would have thought Hanako was the bad guy. I think the reason some would say Tsukasa is Hanako's prized posession is because they seemed to be very close when they were alive and Hanako seems to be incredibly guilty over having murdered his own brother. Tsukasa doesnt seem to feel any sort of grudge against Hanako for it though. If anything I think Tsukasa is just incredibly disturbed and twisted and always has been. He doesnt differentiate right from wrong or pick up on social cues and seems to have "fun" by tormenting other people. He just thrives on chaos. I have reason to believe that Tsukasa might have been the one who physically abused Amane in the past (I mean that chapter when Tsukasa was like "let's play the way we used to" when he was trying to taunt Hanako and basically challenging him was a big indicator for me). Think about it, when Amane was confronted about his cuts and bruises by Tsuchigomori, Amane said that even if no one else would forgive such acts, he was still willing to forgive it. What other reason could it be other than because it was his own brother that did it? It was maybe a matter of time before Amane couldnt take it anymore and decided to end the torment. Only time will tell and clear up all our doubts and questions though lol these are all just theories at this point so who knows.

yeah, I find that theory very logical. No.7 mentioned to his teacher, No.5, that even if other people find that the acts (of abusing a person physically) wrong, he will still forgive it. The only reason I can think of is that it's because the perpatrator is his own brother, which is why he will condone it.