Hebi

After thinking about it and reading more online I feel like Chishiya was supposed to be in that role. It would make more sense for Banda to care about him, because they were in a game together.

They probably had to change the story after the actor for Chishiya had mental health problems and couldn't return to play a big part.

One of the weirdest things to me was Banda. Has he ever even met Arisu? Why does he care about him so much?

I at least wish we got some flashbacks or proper backstory for Banda.