Demiurge

Demiurge serves as the Guardian of the Seventh Floor of the Great Tomb of Nazarick, where he is in charge of planning the stronghold's overall strategy and defenses. He appears as a demon dressed in a sharp business suit and glasses, a calm, almost bureaucratic look that hides just how dangerous he really is.

Widely regarded as one of the most intelligent and most ruthless of Nazarick's guardians, Demiurge has no hesitation about committing cruel acts if he believes they serve his goals, and he enjoys watching his careful plans play out even when they cause real suffering. He rarely shares his full plans with the other guardians, instead letting them believe that Momonga personally directs every detail, when in fact Demiurge often works out the specifics himself and gives Momonga the credit.

In the human world above, Demiurge operates under the alias Jaldabaoth, posing as a fearsome "Demon Emperor" leading armies of monsters against humanity, using this disguise to conquer territory such as the Abelion Hills and to seize control of a criminal organization called Eight Fingers. Within Nazarick, he gets along well with the other guardians, sharing something close to friendly rivalry with the insect warrior Cocytus, though his relationship with the guardian Sebas stays tense because their creators held very different views on how to treat the world beyond Nazarick's walls.