Jepperd is one of the main characters in Sweet Tooth. He is a crude man who rescued Gus from other hunters. He plans to take Gus, whom he named Sweet Tooth, to a safe place called the Preserve.
It is later revealed that Jepperd is in fact a bounty hunter, and plans to lead Gus to the preserve, but it is far from the fabled save haven that he made it out to be.
In the In Captivity arc, Jepperd is fleshed out. We learn why he does what he does and he once had a family. We also learn he was once a Hockey Player.
Writer Jeff Lemire takes the opportunity to pay homage to another indie cartoonist he calls a friend and has Jepperd fight Jeffrey Brown. Lemire has commented on this on many sites, most notably on the Vertigo Blog.
In the Animal Armies arc Jepperd fights with his morals and this is the arc of his redemption. He would round up a team to libertate Gus and is fellow Hybrids. In Animal Armies we see a more caring and less cold Jepperd.