Franz Kniprode was a Temerian mage, or more precisely, a necromancer able to summon zombies who resided for time near the Old Castle. He appeared only in a 2004 video of The Witcher video game, and not in the final cut, although a model similar to his was later used for Everden of Rinde in the Side Effects add-on.
In the demo, Kniprode asked Geralt for help in getting the skull of Foltest's grandfather, because there was something in the skull that would help revive his dead wife. The witcher then went to the catacombs where he ran into Halfar and his thugs, and was faced with a decision. He could either kill them or send them away, before killing a koshchey and getting back to Franz.