Is Cain bad

Cain killed his brother Able because he was jealous because Able was the king's favorite brother. I don't think that Cain is bad but that he had some mental problems or something like that (anger management issues ect.). What do you think?

Yes. He was a bad guy. For his jealousy and "rising up to slay his own brother". God cursed Cain to an eternity of wandering the earth restlessly with barren harvests. Gen 4: 10-12.

Plus, God marked the guy and ordered no one to touch him. Gen 4:15 That's got to be a bad guy in my book.