Jack keeps his hair very short, and wears a tactical trenchcoat that affords little to grip onto. While on a mission, he uses his van as a mobile headquarters, living out of the back of it for weeks at a stretch. He is often mistaken for a war veteran struggling with the return to civilian life; he has the same general look, social awkwardness, and thousand yard stare.
Jack is a member of a small but elite international vatican-sponsored religious based secret society whose purpose it is to oppose vampires.
Jack was told from childhood on that his parents and sibilings had been killed, which fueled a thirst for vengeance in his heart and drove him to excel
excel in the vigorous training the order subjected him to as they honed the boy into a weapon against the bloodsuckers.
Jack learned the ancient fighting style, optimized specifically for the slaying of vampires, of the order. Jack learned how to craft various alchemical compounds and weapons curated
by the order for their effectiveness against the leeches. Jack learned the tradecraft necessary to root out and find vamps hiding in plain sight among normal people.
He mastered every practical discipline the order practiced, and was trusted to help elder brothers in actual hunts by his mid-teens. By his early twenties he was leading
hunts. By his late twenties he was capable of killing solo vampires one on one, a very difficult feat. And he was just getting started.