Dr. Mikeneko is an anime-exclusive character appearing during the first half of the series under Daimaō's reign. He served as a mad scientist whose cat-like physical appearance directly shaped his inventions, which prominently featured feline designs, most notably his creation Nyandaber.

Dr. Mikeneko has a sister named Shironeko, the sole female member within their antagonistic group of cat-themed characters. Shironeko undertook an espionage mission against the protagonists, specifically tasked with swapping Chacha's Princess Medallion for a counterfeit. During this mission, she developed genuine romantic feelings for Seravy, creating conflict between her duty to the antagonists and her personal emotions. This turmoil resolved when Shironeko and her brothers collectively recognized they were free from obligation to continue their adversarial roles, allowing them to cease hostilities and find peace.

The character and his family's narrative concludes with their departure from villainy; they do not appear in subsequent story arcs or media beyond the anime's initial conflict period.