Arthur Graves was the first known Gormogon serial killer to appear on Bones.
Background
Not much about Arthur's background is revealed, other than that he was the oldest known Gormogon serial killer. When he was younger, he killed a number of people, cannibalized them, took some piece of their skeleton important in their professional lives and added them to a silver skeleton model. Eventually, he killed enough to put together an entire skeleton. In the 1970s, he worked for the Social Services. He handled foster children, some of which, it can be presumed, he recruited as his apprentices. Among his apprentices was the "current" Gormogon, who, following in his master's footsteps, recruited an apprentice of his own: Jason Harkness. In the meantime, the aging Arthur suffered Alzheimer's and was confined to a nursing home, where his apprentice sometimes visited him. He was usually very calm and friendly there, though a staff member noted that he was "a bit particular about what he [ate]". Prior to being hospitazed, he somehow had all his teeth pulled out with a pair of pliers and gave them to his apprentice, who later used them as shrapnel in a bomb aimed at Booth and Brennan. They go to question him at the nursing home. When Brennan tries to confront him, he hisses at her hostilely.