Jeff is kind of an asshole, but there's more to him than just that. On one side he's a protective and caring brother, while the other side of him is just a bloodthirsty serial killer. Overall, he's quite immature and stubborn with a bad temper.

His voice would be rather low and manly for his age, though it can still reach a higher pitch. Normally it would sound gruff and intimidating, but he can put on silly voices when he's messing around