Emperor Warusa reigns as the supreme ruler of the fifth-dimensional Jaku Empire, spearheading its interdimensional campaign to conquer Earth, designated the third dimension. He commands primary antagonists Belzeb, Falzeb, and Taida, dispatching them to execute the invasion. Their strategy involves launching missiles containing Akudamas ("eggs of darkness"), which hatch into Jaku Beasts—monsters born from human negativity and daily frustrations.

Throughout the series, Warusa's leadership is defined by mounting frustration and anger towards his subordinates' repeated failures against the Earth Defense Class and their inability to capture the defenders' base. This culminates in his direct intervention during the main series climax. Ultimately defeated in Episode 50, Warusa's loss critically weakens the Jaku Empire's grip on Earth.

Warusa's legacy persists in the OVAs. The fifth-dimensional entity Gokudo emerges as a new antagonist, seeking vengeance for Warusa's downfall. Gokudo captures Belzeb, sealing him as a tattoo on his back—a symbol of the conflict ignited by Warusa's reign. The documented materials provide no additional details regarding Warusa's origins, personal history, or activities beyond these events.