Anyone who tells you that they are trained to kill and feel no remorse is a punk and they are relying on a story to scare you, which happens to be working in your case. Same goes for anyone who tells you before a fight that they are a blackbelt or whatever. It's a last minute plea bargin.
On the other hand you're a 5'7 white dude with a bowl haircut who is broke and smokes weed all day so he will probably kick your ass anyway.\
Carry on.