Tartareous is a prison realm located within the Ythen. Each Ythen holds the entrance to the realm inside of them, and will consume offenders of the Seeds, damning them to this inescapable realm.
Tartareous serves as a prison for Arkn and Dekn who violate the rules of the Ythen in Ersis. Arkn and Dekn who commit crimes are consumed by one of the Ythen, thus entering the prison. The realm itself connects into the mind of the prisoner and creates a hellscape when prisoners are connected. The only consistency with each connection is the sub-realm's guide, a shape-shifting entity living in the Ythen known as Zem'phes.