Hieronymus was the Resident mage at Kaer Morhen during the time when the fortress was sacked by a peasant mob.
Biography[]
Hieronymus was a renegade mage who eventually became the resident mage at the witcher School of the Wolf. He resided in a tower close to the keep and the Bastion. While serving as the school's mage, he had an assistant named Chird.
Besides presumably performing the witcher mutations on candidates, he also conducted research into teleportation using crystals. His research was aided when the witcher diagrams left behind by the legendary witcher Elgar were discovered by the school's fencing instructor, Varin. However, it was Hieronymus who uncovered the hidden chamber containing these diagrams and notes. The notes indicated that following certain instructions would lead to other diagrams Elgar had hidden across the world.
Hieronymus and Chird worked to decipher the diagrams, with Hieronymus also translating the notes into clear instructions so that his assistant could eventually locate the other diagrams. After some time, and following repeated urging from Varin, Hieronymus completed his work on the steel sword diagram and gave it to Varin, while Chird continued working on the silver sword diagram in the workshop in the old watchtower.
While deciphering the diagram, Hieronymus also uncovered a new alloy that improved the magical conductivity of the second crystal for his teleportation research. He applied this discovery and placed the crystal outside the tower to charge it with solar energy. As he was writing down these developments, he noticed a fire in the distance and heard commotion outside his tower—a peasant mob was attacking the valley and had reached the tower.
Seeing that the way was blocked, Hieronymus grabbed the diagrams and jumped through an unstable portal just as the peasants broke into the tower. Tragically, the teleportation had fatal consequences—his spine was broken, and his liver or spleen was pierced, leaving him unable to move. He hoped in vain that Varin would come to his rescue, but he died after writing one final note.