Bob

When Harry doesn't know what he's up against, he asks Bob. Bob knows spells, creatures and rules of the magical world no book in the house explains, and loves reminding Harry of it.

On the show, Bob appears as a full figure, clothes and all, that only Harry can see. In the re-edited pilot, he's just a voice tied to the rune-covered skull.

The skull belonged to Justin Morningway, Harry's uncle. When Justin died, Bob passed to the nephew. They live like old acquaintances: Bob saw the uncle up close and knows family secrets Harry would rather not hear.

Before he was Bob, he was Hrothbert of Bainbridge, a sorcerer killed by an axe blow in 900 AD. He was executed for using black magic to raise Winnifred, the sorceress he loved, and his soul was sealed into his own skull. In "Soul Beneficiary," a case drags a dark secret from that past into the light.

Terrence Mann plays a full-bodied Bob who walks around the house, comments on everything and bickers with Harry like an old roommate. That was the show's choice. When the pilot was re-edited, Bob went back to being just a voice coming from the skull, closer to what readers knew.

Either way, his job is the same: Bob knows what Harry doesn't, and charges for it in sarcasm.

In "What About Bob?", a woman Harry gets involved with steals the skull and takes it to Justin. Without Bob, Harry loses his adviser right when he needs him most, and learns his uncle has plans to come back.

In the books, Bob isn't a man's ghost: he's a spirit of intellect bound to the skull, living in Harry's lab and showing only as lights in the skull's eyes.