Nyan is an extraterrestrial feline from a red star in the Felis constellation, tasked with exchanging "happy energy" between Earth and his home world. Adopted by a human girl named Haruka after arriving on Earth, he formed bonds with local cats and actively protected them from criminals stealing cats for the pet trade, demonstrating his protective nature and deep connection to both humans and felines. He possesses the unique ability to transform into the empowered Ultra Nyan by passing through his tail ring, the source of his powers. In this enhanced state, Nyan wields several abilities: generating the Mankiumu Beam attack from a beckoning cat pose; telekinetically manipulating objects with his tail; transmuting matter (such as changing wire into a rose, debris into doves, or a vehicle into a whale); sustained flight; telepathic dream communication; transferring collective "happy energy" via a pink energy beam; and creating energy platforms for rescue operations. His powers have specific limitations. Damage to his tail ring compromises his abilities, requiring regeneration time for recovery. Additionally, exposure to adhesive substances like tar completely prevents his transformation. His performance metrics include a maximum flight speed of 881 km/h, running speed of 194 km/h, underwater speed of 41 km/h, subterranean speed of 56 km/h, and a jumping height of 45 meters. A significant challenge emerged when Haruka developed allergies, forcing Nyan's temporary relocation to a friend's house. This separation caused him profound sadness and diminished vitality. Concurrently, his neighborhood feline sanctuary faced aggression from crows displaced by habitat loss and suffering chemical-induced irritability from adulterated food. Prioritizing peace, Nyan focused on curing the crows' ailments and preventing interspecies conflict. He intervened non-violently, calming the aggressors and using his powers like matter transmutation to de-escalate hostilities rather than engage in combat. Beyond these events, Nyan made a non-narrative cameo appearance as a costumed performer in *Ultraman Tiga: The Final Odyssey*, marking his sole documented appearance outside his dedicated adventures.