TV-Series
Description
Nemesis, younger brother of Tatsunori Kinniku and member of the Perfect Chojin faction, was born Sadaharu Kinniku into the royal Kinniku family. He displayed exceptional wrestling talent early, mastering the Muscle Spark technique at thirteen—an achievement tragically resulting in his sparring partner's accidental death. This event led to his imprisonment in Planet Kinniku's underground dungeon, his existence erased from history. Facing execution, he escaped and encountered Mirageman at Mont Saint Parfait. Recognizing Sadaharu as Silverman's descendant, Mirageman facilitated his rebirth as the Perfect Chojin Nemesis.

While imprisoned, visits from Harabote Muscle and Mayumi Kinniku explained his absence prevented civil war; he affirmed his loyalty to Tatsunori. Witnessing Planet Kinniku officials attempt to assassinate Tatsunori solidified his resolve to eradicate corruption by purging the planet through the elimination of the Kinniku Clan and their allies, motivating his return to Earth as an antagonist.

Leading the New Perfect Large Numbers in the Perfect Origin Arc tournament, Nemesis initiated hostilities by demanding Peek-a-Boo commit suicide per Perfect Chojin ideals. He countered Kinnikuman's intervention with a Muscle Spark. Later, he partnered with Polarman to execute a Busters Docking maneuver on The Machineguns. Progressing through the tournament, Nemesis battled Robin Mask on the pyramid's sixth ring. After a brutal fight employing techniques like the Nemesis Driver, Battleship Sinker, and Tombstone Driver, he defeated Robin Mask and discarded the body into the sand dunes.

Following Polarman's loss to Warsman, Nemesis entered the ring and forced Polarman to stab himself with his own hand, enforcing Perfect Chojin doctrine. He discarded Polarman's body alongside Robin Mask's. Nemesis revealed the Perfect Large Numbers' mission: to judge and eradicate powerful chojin, preventing a resurgence of ancient brutality. He cited the spread of Friendship Power as a threat, identifying Kinnikuman as central to this imbalance.

Nemesis traveled to the Chojin Graveyard seeking Chojin Enma, encountering General Devil instead. Revealing his Kinniku Clan heritage, he attacked General Devil, who rebuffed him for not being one of the ten Origin holders. Nemesis pursued General Devil to National Stadium, declaring his intent to protect Strong the Budo. During the tournament's Yggdrasil stage, he faced Ramenman as his next opponent.

Initially dismissive of Kinnikuman, Nemesis developed respect during their conflict, recognizing him as Tatsunori's worthy successor. Despite ruthless methods, he harbored deep concern for Planet Kinniku's welfare and maintained unwavering respect for his brother Tatsunori, extending this regard to Tatsunori's successors like Mayumi and Kinnikuman. His personality shifted from merciless adherence to Perfect Chojin doctrine to displaying care for his family and planet, ultimately growing into an ally.

Physically, Nemesis shares similarities with Kinnikuman but possesses bluish skin, yellow eyes, and lightweight chest armor. His mask features red "eyebrows" forming a battle mask, with the kanji for "Perfect" (完) adorning his forehead.