 As a spirit of knowledge, Bob has served various wizards over the years and functions much like a magical encyclopedia, assisting Harry with various tasks; such as making potions, preparing difficult rituals, and providing him with useful information about the various supernatural creatures Harry deals with throughout the books (since Harry's magic causes almost all modern technology to malfunction in his presence, he does not own a computer).Although he frequently ribs Harry for being too stiff/noble, and he lacks a firm understanding of moral values, Bob is truly afraid of dark magic while under Harry's ownership.He panics when Harry shows him a drawing of one of the sigils for the Order of the Blackened Denarius and urges him not to confront the group.