Cregennan (also Cragen) of Lod was a mighty human sorcerer, most famous for falling in love with an elf, Lara Dorren, and for being murdered for it by humans. Their daughter, Riannon, was adopted by Cerro, the queen of Redania. Cregennan was one of the ancestors of Ciri.
Born to at least one magical parent, Cregennan graduated from the magic academy summa cum laude and shortly afterwards became famous as the unbelievably talented (for his age) mage. He pushed for coupling elven and human doctrines of the magic and was a great follower of the idea of proximity and coexistence of the two races. He was liked and accepted by elves.
The more and more ambitious and (surprisingly) more and more viable plans of Cregennan were interrupted by his love affair with Lara Dorren aep Shiadhal, elven sorceress from the group of so-called "Sages". Interestingly, this relationship infuriated humans more than elves. Furthermore, when Lara Dorren became pregnant, Cregennan was accused of treason, cahoots with elves, and scheming a plot against his own race. When he refused to break up with her and the elves, the treacherous attack on both lovers was done. Cregennan was killed, Lara managed to escape.
The legend has it that "Cregennan's Grave" is located in the enormous glacial erratic near Rinde. In fact he had to be buried closer to the place where he had been murdered, i.e. in the hamlet Foam by the river Pontar.
Many elves, seeing his relationship with Lara Dorren as stealing from their heritage, didn't wish to acknowledge the relationship. As such, when a sculpture was made of Lara Dorren to serve as a stand-in gravestone for her, Cregennan was left out of it, though the statue was made in such a way that it was clear another being was supposed to be in the sculpture. This sculpture can be found in the elven cemetery of Tir ná Béa Arainne, which is in a cave under Mount Gorgon. Aen Elle considered his relationship with Lara a theft of their heritage, and the king of the Aen Elle, Auberon Muircetach was determined to take back that stolen heritage, by using Cregennan's descendant, Ciri, to produce an heir.