Remember him?
I thought not.
Anyway, Jak's one of those people who'll shuffle up to you and say in a low tone of voice, "hey, want some grenades from my van? I heard they're the secret cure to cancer."
He usually makes shady deals with people, whom he later uses to get himself out of the messed up situations he gets himself into.
Personality-wise, he's very self centered, though (unfortunately for you) clever and quick witted.
Sneaky too, I'm afraid...
#Jak