Who is Vern Bogner from Geek Love and what is their importance?

Vern unintentionally defines how Arty feels towards "norms" in one single afternoon. After attempting to kill the children and Crystal Lil, Vern is put in jail and then a mental institution. Upon release, he kidnaps his children and kills his wife, putting him back in jail. When budget cuts put him out on the street again, he contacts Arty for a job. Despite his chaotic history and the fact that he once tried to murder Arty, Arty hires him to be a slave to his commands, owning him like everyone else in the Fabulon. Bag Man eventually impregnates the twins through a quasi-rape, producing Mumpo.