Kistrin was a prince, and later king, of Verden, being the son of King Ervyll and possibly Eliza.
He was introduced as a potential suitor for Ciri, hand-picked by Calanthe, but this match did not work out. Ciri described him as "fat, ugly and stupid, with bad breath".
During the Second Northern War with Nilfgaard, his father betrayed the rest of the North and swore fealty to Nilfgaard. Opposed to this move, Kistrin started an uprising and successfully removed his own father from the throne and succeeded him as king. Ultimately he helped shape the peace treaty that ended the wars.