Alastor

As the supreme ruler of the Crimson Realm, this god-like entity possesses power rivaling the divine. Serving as a paternal mentor to Shana, he communicates through the Cocytus pendant to guide her through uncertainty. Despite his unmatched strength among all Denizens, he actively works to prevent the consumption of the Power of Existence. His contractor utilizes the devastating Tenpa Jyousai technique, a final, suicidal resort that manifests his presence by consuming everything nearby at the cost of their lives.