Crepus Ragnvindr, known as Master Crepus to some, is the deceased biological father of Diluc and adoptive father of Kaeya. Prior to his death, he was the head of the Dawn Winery. He and Diluc are descendants of the Dawn Knight Ragnvindr. His untimely death, which occurred around three years prior to the game's events, caused the falling out between Diluc and the Knights of Favonius. The infamous Fatui are connected to the cause of his death.