There’s a short story by Harry Turtledove (of alt-history fame) about Jesus actually being bitten and turned by a vampire at the time of the Crucifixion. And that Peter had him hidden away in a chamber at the very bottom of his namesake Basilica, taken care of by a secret order whose existence was known only by the reigning pope. And that a ceremony was performed where each new pope would allow Christ to feed on some of his blood.