Billy Koenig was a Werewolf and a member of the North American Werewolf Pack. He is only seen in the short story Infusion set in 1946, whether he was a teen or adult at the time is unknown. Billy joked around with other members of the Pack and did not seem to show favoritism unlike other members. Billy is not mentioned in subsequent works and presumably died before the events of the novella Savage set in 1967. Jimmy Koenig who appears in Bitten is of some unspecified relation to him.