When fiends and powerful evil spellcasters are lost beyond the farthest reaches of the multiverse, they sometimes return as horrific undead called devourers that consume the souls of the living to fuel their arcane machinations. Their bodies are ruined and rebuilt, hollow and twisted, even as their minds undergo a spiritual transformation. They gain the ability to bind other souls to their own and drain their essence for magical power, yet can never be sated in their pursuit of it. Seething masses of distorted ghostly shapes surge within their hollow rib cages-manifestations of the devourers' most recently consumed souls.