Paracelsus is an inhabitant of "The World Below" who was featured in Season 1 and 2 as a recurring antagonist. John Pater was a scientist and former friend of Father's who helped organize the Tunnel World. But when he eventually desired power for himself, the community was forced to exile him. Father describes him as a "philosopher, scientist, magician" like the real Paracelsus, the name John Pater eventually takes for himself. When Father tries to reason with Paracelsus by calling him by his real name, he commented "John is dead." Paracelsus' late wife Anna was the one who discovered the infant Vincent near St Vincent's hospital and brought him to Father. Paracelsus tried to lead Vincent to siding with him while disguised as Father, but was ultimately killed by Vincent during a fit of rage. In his dying breath, Paracelsus quotes "At last, you are my son." He was played by Tony Jay, known for his role as Judge Claude Frollo.