Bei Dou might let his snakes eat people, for his own entertainment. It will be bloody and painful, and probably more than one snake on one person. He also has the capabilities to destroy spirits so once he gets bored of watching them suck out people's feelings, he'll start doing that.

Dionysus will mostly be looking out for his friends but that's pretty much it.

Alp will be jumping into people's minds as a cat to investigate their odd state, but he's just a cat in the end.

Cheshire will stay out of the way and not even be around for this stuff.