Empress Nei began as one of the Four Divine Kings, a homunculus forged by the dark god Anthrasax to serve him. She wielded a massive battleaxe with immense physical strength, remarkable durability, and mastery over dark magic. Alongside her sister Sheila, another Divine King, she executed Anthrasax's commands for centuries—subjugating kingdoms and hunting powerful artifacts.

Her existence shattered when Sheila betrayed Anthrasax. Nei confronted Sheila during the escape, clashing fiercely until Sheila defeated and seemingly killed her. Anthrasax recovered Nei's corpse, performing a vengeful ritual that merged her body with Uroboros, the serpent god of destruction. This resurrection transformed her into Empress Nei, Anthrasax's ultimate vessel for Uroboros. Her form mutated grotesquely: immense in size, scaled, reptilian, and crowned with multiple serpent heads. Uroboros consumed her personality, flooding her with destructive will and seething hatred toward Sheila, though fragmented memories of betrayal fueled her rage. As Anthrasax's final weapon, she embodied pure annihilation, unleashed to eradicate all life.

In the culminating battle against Anthrasax's foes, Empress Nei unleashed devastation until Sheila confronted her directly. Sheila's raw love and remorse pierced Uroboros's corruption, searing Nei with psychic agony. A fleeting internal struggle surfaced—Nei's original consciousness emerged, whispering sorrow and love to Sheila. But Uroboros violently crushed this resurgence, drowning Nei's identity. Empress Nei perished when her core shattered, her monstrous form disintegrating into nothingness.