Pontiff Sulyvahn discovered Irithyll. He was directly connected to Aldrich and was the one that imprisoned Gwyndolin to be devoured by Aldrich.
Pontiff Sulyvahn bestowed a special ring upon his knights. The ring caused those who peered into the black orb upon it to be lured into battles of death, transformed into frenzied
beasts. These rings were only granted to those knights who were dispatched to foreign lands.