Kenzou Ooyama (Ken O'Donnell in English adaptations) is the CEO of Eternal Earth corporation. He establishes the artificial habitat Neo Jungle, presenting himself as a benefactor relocating animals displaced by habitat destruction and initially perceived as the "creator of nature." His motivations extend beyond conservation to a desire for control and domination over Neo Jungle's life, culminating in an ambition to "become the creator of all life and replace God," reflecting a profound power-seeking agenda.

His relationship with his son, Kenichi (Kevin in English), is complex. Kenichi frequently sneaks into Neo Jungle's restricted zones, bonding with animals—particularly Leo, the young lion son of Panja. Ken O'Donnell disapproves, scolding and grounding Kenichi upon discovering these unauthorized activities. He also harbors an unspecified grudge against the animal Toto.

A critical turning point occurs when Elder Dolf contracts a virus and is transported to a laboratory. Ken O'Donnell responds by initiating a system reset of B-Block, the sector housing elephants, zebras, giraffes, tigers, hippos, lions, and other species. This decision triggers a full-scale uprising led by Leo. During the conflict, Leo attacks Ken O'Donnell while carrying Kenichi's phone, forcing the CEO to confront the consequences of his actions and realize the need to protect his son. Ken O'Donnell is subsequently incapacitated by an explosion.

After the animals depart Neo Jungle to return to their natural habitat, Ken O'Donnell is shown being dragged away by a hippopotamus. His arc traces his path from a position of authority and perceived benevolence to becoming the primary antagonist whose actions instigate rebellion and lead to his downfall.