TV-Series
Description
Nekomamushi, also known as Cat Viper, is a prominent character from the anime One Piece. He is a feline member of the Mink Tribe, a race of humanoid animals, and serves as one of the two rulers of the Mokomo Dukedom on the back of the massive elephant Zunesha. Specifically, he holds the title of Ruler of the Night, governing the kingdom from 6:00 PM to 6:00 AM. He is also the guardian of the Whale Forest on Zou. As a faithful retainer to the Kozuki family of Wano Country, he is a member of the Nine Red Scabbards, a group of powerful warriors loyal to Kozuki Oden.

Physically, Nekomamushi is a large and imposing figure. He has yellow fur with dark brown stripes and a thick, striped tail. He keeps his wild, bushy blonde hair styled in a way that resembles a lion's mane, and his appearance is further distinguished by a prominent scar running down the left side of his face. He typically wears a large, decorated robe, a haramaki around his waist, and often smokes a kiseru, a traditional Japanese pipe. After being tortured by Jack of the Beasts Pirates, his left hand and part of his forearm were lost; he has since replaced them with a prosthetic double-barreled gun.

Nekomamushi has a bold, freedom-loving, and unrestrained personality. He is known for being aggressive and merciless, especially towards his enemies, and can be incredibly stubborn, once ignoring doctor's orders to rest. Despite this, he possesses a deep sense of loyalty and genuine care for his friends and fellow Minks. His willpower is immense; he endured extensive torture and lost his arm protecting a friend, Raizo, rather than betray his location. He exhibits many feline behaviors, such as enjoying playing with balls and cat toys and liking catnip, though he is noted to love baths, unlike most cats. He also has a unique laugh, displayed as goronyanya. Conversely, he is afraid of injections and, being a cat, has difficulty eating very hot food.

Nekomamushi's backstory is deeply intertwined with the history of Wano. In his youth, he left Zou and journeyed to Wano, where he became a retainer to Kozuki Oden. He accompanied Oden on his voyages, serving as a member of both the Whitebeard Pirates and the later Roger Pirates, granting him high navigational skills and a wealth of experience. After Oden's death and a falling out with his counterpart Inuarashi, he returned to Zou to rule during the night, which allows him to avoid his former friend. When Jack attacked Zou in search of Raizo, Nekomamushi fought the pirate for five nights, alternating shifts with Inuarashi. After being defeated by a poison gas weapon and tortured, he was saved by the Straw Hat Pirates. In the present story, he becomes a key ally, joining the Ninja-Pirate-Mink-Samurai Alliance to take down Kaido and avenge Oden. During the raid on Onigashima, he fought against Kaido's forces and later avenged his fallen comrade Pedro by defeating Charlotte Perospero.

His primary relationship is with his counterpart, Inuarashi (Duke Dogstorm). Once close friends, they have a bitter and ongoing rivalry that forces them to rule at separate times. However, their loyalty to the Kozuki family allows them to set aside their differences when needed. He is fiercely loyal to Momonosuke and the memory of Oden. He also shares a strong bond with his fellow Minks, including the late Pedro, and holds great gratitude towards the Straw Hat crew, especially Tony Tony Chopper, who treated his injuries.

As a Mink, Nekomamushi possesses superhuman physical abilities, including immense strength, speed, agility, and endurance, allowing him to fight powerful enemies for days. His species-specific ability, Electro, allows him to generate and channel electricity through his body or weapons. He is a highly skilled combatant, proficient in using a bladed staff and even emulating Oden's swordsmanship style. His most powerful transformation is Sulong, triggered by looking at a full moon. In this state, his physical capabilities and Electro are massively amplified, making him strong enough to overwhelm formidable opponents like Jack and Perospero.