 Harry apparently gave him the name Bob, the only name that the spirit has had.According to Luccio, in "Small Favor", it is stated that Bob was a "Mini-Archive," but the wardens had destroyed him, when Kemmler was brought down and killed.Instead, DuMorne—a Warden at the time, but already at least planning to turn traitor—did not destroy Bob and took the skull into his possession, whence it then passed to Harry after the two dueled.