Enma Daiou rules Hell in Japanese Buddhist tradition, presiding over deceased souls' judgment and assigning their destinations based on recorded deeds. He oversees a bureaucratic system staffed by secretaries and demonic servants, enforcing punishments for sins. His nature embodies a paradox—fearsome yet compassionate—as he seeks to save souls from eternal suffering despite administering damnation. His origins derive from the Vedic god Yama, evolving through Chinese Buddhism before integration into Japanese folklore; his judgment hall mirrors Tang Dynasty administrative structures.

In *Ghastly Prince Enma Burning Up*, Enma Daiou dispatches his nephew, Prince Enma, to lead a demon patrol recapturing escaped yokai disrupting the human world. This mission prioritizes recovering lost subjects over human welfare. He equips Prince Enma with a fire-based staff and the "Fire Crown," a device created by the prince's parents to suppress his excessive lustfulness following inappropriate advances toward his sister, Enpi. The crown's significance surfaces when rebellious demons attempt to seize it.

Enma Daiou covertly collaborates with Heaven on a scheme to harvest "psychowatts"—energy derived from human souls—to power both realms. This plan requires triggering a global catastrophe to maximize soul collection, rendering humanity expendable fuel. His daughter, Enpi, initially opposes this genocide, advocating universal pleasure instead. She later aids Prince Enma in exposing the conspiracy, using the Fire Crown to redirect his lust into a cosmic energy surge during a mass orgy between angels and demons. This event generates sufficient psychowatts for both realms, leading Enma Daiou to abandon the genocide.

His character blends mythological gravitas with absurdist traits, displaying flamboyant mannerisms and an overbearing demeanor that unsettles subordinates. Despite his station, he demonstrates flexibility by accepting alternative solutions to Hell's energy needs when presented with overwhelming evidence.