Does he devour them one after another? Does he mount them along the halls of an eldritch temple, or pickle the souls in necromantic brine? Is he merely a puppet, pushed through the dimensional rift by a demonic puppeteer? Such is his evil, so intense his aura of darkness, that no rational mind may penetrate it. Of course, if you really want to know where the stolen souls go, there's one sure way to find out: Add your soul to his collection. Or just wait for Nevermore.