what are some instances we have seen so far that reveal the violent streak in Jack up to this point? (Chapter 1 and 2)

Jack has the makings of a sociopath from the beginning of the story. He handles "his" choir of boys like a dictator ready to have a tantrum if things don't go his way. He also has a penchant for taking out his dagger and waving it in the air or striking a tree. He does this to validate his self-esteem that is built on shows of violence and control.