Thunder, known as Zundar, is a hedgehog-like alien from an uncharted planet, commanding the Conquest Club as a central antagonist. Driven to conquer Earth by cultivating hatred and dismissing love as a "foolish emotion," he orchestrates schemes to weaponize human negativity. His agents manipulate individuals into manifesting monsters from their darkest emotions, forcing protagonists to confront these threats.

He sports green quills and an arrow-shaped head marking, communicating through faint snout motions rather than speech. The name "Zundar" hints at a connection to "zunda," a vibrant green mochi, though unverified. His signature weapons, Zundar needles, extract and magnify human malice. Initially presented as scarce resources, he deploys them recklessly when assisting his superior, Lord Hireashi—exposing his subservient position within their hierarchy.

While manipulating Conquest Club members to advance his agenda, his unwavering loyalty to Hireashi underscores his role as a subordinate enforcer. A commanding facade masks his reliance on higher authorities, culminating in the first season’s climax. Once perceived as an autonomous villain, he is revealed as a pawn within a broader conquest mechanism, his authority contingent on forces above him.