At first Toshi is a mentally fragile weak little boy who can't stand up for himself.
He cries for everything and nothing.
After he meets Mon, who shows him without mercy how a man could be if he fights for everything he wants, Toshi starts to metamorphose into a much more evil human than Mon.
Toshi loses his mind against the thing he turns into
and is unable to be any longer a running member of society.
He becomes a devil with a fanatical thirst for destruction.