Dr. Zéro holds the position of chief medical officer aboard the starship *Arcadia*, frequently locking horns with the ship’s steward over his habit of pilfering sake from the kitchen—a recurring source of comedic friction. His constant companion is Mi-kun, a cat he adopted after its injured mother led the kitten to him in a moment of desperate trust. Mi-kun remains a fixture aboard the vessel, appearing in numerous storylines throughout the franchise. Though his duties involve coordinating medical crises alongside the crew, his presence often anchors lighter, humorous interludes. The circumstances of Mi-kun’s adoption—born from an injured creature’s plea for aid—subtly underscore the compassion woven into his otherwise mischievous demeanor.