Runba, bearing the full name Rumba Lu Seine Tercero or Rumba Luseine III, is a Komondor dog living within the Saitama residence shared by the main HxEros team. His distinctive white coat reflects the standard appearance of the Komondor, a Hungarian herding breed. Within the story, he serves exclusively as a non-combatant companion animal, remaining entirely separate from the HxEros team's battles against extraterrestrial adversaries. Runba forms a special bond with Maihime Shirayuki, a core team member, and visibly perks up with enthusiasm whenever she feeds him; this food-motivated interaction stands as his most consistently depicted behavior. Across the manga, primary anime series, and supplementary OVA releases, his presence remains confined to this domestic role, with no substantial background, character development, or expanded narrative function presented.