Paradisi won the subtle knife in a fight with its previous owner. In this fight, he lost the ring and little fingers of his left hand, which marked him as the new bearer. In Bakn on the Caspian, Paradisi met John Parry who healed his wound. In exchange Paradisi told Parry about Æsahættr.
At some point, Paradisi was imprisoned in the Torre degli Angeli by Tullio, a young man from Cittàgazze trying to keep the spectres away with the knife. William Parry fought Tullio and became the new bearer of Æsahættr, losing the same two fingers as Paradisi. Once freed by Will, Paradisi taught the boy the art of the knife. After the training, Lyra and Will left the tower, and Paradisi committed suicide to avoid being attacked by the spectres.