The infernal realm overflows under mass death and ejects demons that can return only with an additional soul.
Carl already knows Sheol as a lethal heat environment and the source of Emberus's fire. The Demon Eviction announcement reveals a second function: the underworld receives battlefield dead and can become overloaded.
When its powers expel unwanted demons upward, those entities seize shells in the living world. A successful grapple opens a return portal and drags both demon and victim into Sheol, producing automatic death for the captured crawler.
A vast red underworld crowded with souls, demons thrown upward through cracks while grapple portals open above.
Sheol is both destination for battlefield souls and the origin and endpoint of Demon Eviction predators.