And then we know that the blonde guy hated his aunt and uncle who took him to the states because according to him they only wanted him for money. So I think he got rid of them as well so he wouldn’t have anyone holding him back so he would be able to return to the mc quickly.
And the blonde guy isn’t affected by the mirrors and the hands because he spoke with the demon in the mirror in that one flashback the teacher had so he’s not afraid and I think the hands are from all the people he has killed or that have been killed over time and that wtv demon that gave him that ability has been making the same deal for centuries since one of the ppl said that the earliest case of that dates back to the 18th century.
And I think the last bit of memory the mc is missing IS THAT NIGHT where they struck the deal and maybe the mc hallucinates because he also made the deal since he said he felt powerless to help and stop adults from bullying him so he didn’t want to feel like that but then after the parents died and ppl saw him he decided to forget and the reflections are prolly the demon talking to him so he will remember the deal which is probably something like the demon helps get rid of the bad people who hurt/take advantage of them and in return they have to kill people to feed the demon or give it energy or something.
Your theory is good ! Can't wait to see what happens next chapter.
Situational irony
I discussed it with a friend so I thought I’d shar it here ahhh I can’t wait to find out what the big mystery is
What does this mean
We know something the main character didn't know
The blonde one struck a deal with some typa demon or sumthing that would allow him to get rid of his parents BECAUSE they were abusive, and I think it happened on the night when mc went thru the window and ended up getting thrown into the room with the black door along with the blind guy. And in that darkness sumthing like spoke to the blonde guy and you know because they were kids it probably presented itself to both or only the blonde kid, and I think when his parents went back into the room to get the kids out THATS when the blond guy killed his parents, and the reason mc can see the hands too is because he was there when the deal was struck or something.