Pazuzu stands as a primary antagonist in the narrative, a demon king who has occupied the tower for centuries. His fearsome appearance features wings, sharp talons, and a prominent horned head. He wields ruthlessness, charisma, and cunning intelligence, frequently manipulating others to achieve his ends. Magical abilities are central to his power, and he commands shadow knights to eliminate threats.

He is the father of Henaro, a relationship that later motivates her infiltration of Jil's group. Pazuzu's antagonism towards King Gilgamesh peaks in an unsuccessful assassination attempt during the second episode. His capacity for violence is evident when he kills Kally within the tower.

During the Summer of Anu event, Pazuzu actively obstructs climber groups ascending the structure. His reign as a major adversary ends when Neeba defeats him. Though physically destroyed, Pazuzu's influence endures indirectly through his daughter. In the sequel series, his illusion manifests within the Garden of Illusion in the Mythical Tower, where Henaro confronts and destroys it.

Pazuzu's background establishes him as a longstanding demonic entity within the tower's hierarchy, fueling conflicts involving climbers and established powers like Gilgamesh. His legacy persists beyond death through both familial bonds and lingering illusions.