Styx

AKA-
 * The Wraith
 * The Amortal One
 * Carrier of River Styx
 * The Betrayed Betrayer
 * The Damned Martyr of Corruption
 * Formerly, The Caster Alchemy

Styx is a product of soul mutilation from the Rifter Shak'iri under the influence of Grace Lernae using the Spire of Paradisum. He is the purpose of one of 4 Sacrifices for the 5th seal because, only from "the Never-Existing Soul of a Wraith" could the 25% of the seal be broken. Grace re-named The Caster Alchemy as Styx, from the River of Hate, Styx.