Mayumi Kinniku is a character in Yudetamago's manga and anime series Kinnikuman and its sequel Ultimate Muscle (Kinnikuman Nisei). He is typically referred to as King Kinniku. He is known as Mayumi Muscle in the English-language version of Ultimate Muscle. Despite the name change in the English versions, he is not related to Harabote Muscle in any of the versions of Ultimate Muscle.

Classification: Seigi Chojin

Homeland: Planet Kinniku

Age: 65, 100 (Nisei)

Height: 193 cm

Weight: 115 kg

Chojin Kyodo: 650,000 Power

Favorite Techniques: Iron Claw, Kinniku Flash

First Appearance: Manga Chapter 3, Anime Episode 1

Mayumi Kinniku is the father of Ataru and Suguru Kinniku and the 57th King of Planet Kinniku. He has the character 王 (Ou) written on his forehead. He is a former Chojin Olympic V2 Champion as well as a Universal Grappling Champion. He has a fierce and long-standing rivalry with Harabote Muscle (the future chairman of the Chojin League), and the two of them frequently appear in Exhibition Matches which are unpopular with the younger fans.

He is married to Sayuri Kinniku, and although she is embarrassed by how he sometimes behaves, the two are very much in love with one another. Much to her annoyance, the only food he knows how to cook is curry. Despite being a descendant of the Royal Kinniku Family (キン肉王家, Kinniku Ouke), he does not know any of the 3 Great Secrets of the Kinniku Clan and never uses the Face Flash.

Because strict training caused his eldest son Ataru to run away, he raises his second son Suguru very indulgently. However, frequently quarreling with Suguru, wanting to strangle his neck as a child because of his stupid face, and mistaking him for a pig and subsequently abandoning him on Earth are just a few of the examples of how Mayumi fails as a father. Nonetheless, whenever Suguru fights, and especially when he's winning, Mayumi cheers loudly for him and brags that he's his son.

His name comes from Akinobu Mayumi.

(Source: Kinnikuman Wiki)