lestermolester
Jack is angel that fought in a crusade against a large band of demons who usually try to snatched the remaining stragglers of angles who were defeated but could still fight. what they would then do is load them up on a delivery truck and drive by each demon's house until they saw the right one for each angel. In Mark's case he always wanted angel that wasn't so broken after the war and could still probably take on a few demons if it got away. so when the demons realized that there was an angel ripping apart some of the demons with unparalleled speed and precision, they immediately grouped around him and started to beat him half to death. then he ended up on Mark's door in a pool of blood when the demon was just getting up in the morning so he was naturally a little angry when the "delivery service" screwed up his treasure.