Kinkotsuman is a character in Yudetamago's manga and anime series Kinnikuman and its sequel Kinnikuman Nisei. His name is changed to Skullduggery in Ultimate Muscle. He later is revealed to be the father of Bone Cold.
Kinkotsuman is an alien who has come from Dokuro-sei (ドクロ星, Planet Skull) in order to conquer Earth. He has the character for bone (骨) on his forehead. He was Kinnikuman's nemesis in the early chapters and was just as silly and stupid as his rival. After his loss to Kinnikuman he reappears with Iwao as his sidekick, and from then on they plot schemes in order to defeat Kinnikuman.
In the original manga he disappears after the series switches to just wrestling, but in the anime he and Iwao appear alongside Detective Gobugari as members of the Seigi Choujin's cheering party for the remainder of the series.
KinnikumanKinkotsuman first arrives in chapter 18 (volume 2) of the manga as an invading alien and challenges Kinnikuman to a fight. Despite using milk (Kinnikuman's weakness) and a monster minion, he is quickly defeated by Kinnikuman and retreats to a life of sworn revenge on him. He creates a UFO hideout (which Kinnikuman likes to poke with a really long stick) and obtains a sidekick in fellow Kinnikuman foe Iwao. Though Kinkotsuman considers himself an evil genius, he is actually quite a stupid and can't even succeed at defeating a loser hero like Kinnikuman. He would try several times to defeat him but would always fail, often due to a gigantic flaw in his plans. He would also occasionally plot against Terryman, the most memorable time being when he used a special mind-control/enlargement gun on Natsuko Shono (Terry's girlfriend).
He and Iwao would then try to foil Kinnikuman's attempts to qualify for the 20th Chojin Olympics, with plans ranging from making themselves invisible and tickling him during a weight-lift to enlarging and mind controlling zoo animals during a party before the semi-finals. They would later try to shoot him after his fight with Ramenman, but Terry took the bullet in his leg (this resulted in him later needing a prosthetic leg). During Kinnikuman's fight with Robin Mask, he, Iwao, and Ramenman supported Kinnikuman (Kinkotsuman even slapped him when he was acting like a coward). After the Olympics, they joined up with Sheik Seijin and Skull Bozu and took part in the American Tag Tournament. Kinkotsuman created the cyborg Black Shadow to be Iwao's partner. Black Shadow had the power of Beauty Rhodes, the brutality of Ramenman, the technique of Robin Mask, and the brains of Kinkotsuman. Because he had Kinkotsuman's brains, he immediately attacked Iwao at the ring of the bell. Kinkotsuman took Black Shadow's place during the second match (Black Shadow had been torn apart by Skull Boze and Devil Magician).
He and Iwao fought against Kinnikuman and Terryman and almost won (thanks largely to dropping the ceiling lights on them), but were eventually defeated by simultaneous neck breaker drops from Kinnikuman. They later stole Terry's prosthetic leg during the final match against The Machineguns (Kinnikuman and Terryman) and the Blood Illusions (Skull Bozu and Devil Magician). After a boy in a wheelchair "fought" Kinkotsuman for the leg, Terry got it back and won the match. After this, Kinkotsuman began to disappear into the background, occasionally showing up in crowds of Choujins during Kinnikuman's fights. His last appearance (in the original manga) was during the last fight of the Survivor Match for the Kinniku Throne, when he, Iwao, and several other Choujins reappeared along Kinnikuman's friends to cheer him on.
In the manga of Kinnikuman Nisei, Kinkotsuman makes his first appearance after seeing the New Generations heading off to Japan.  He then has a flashback explaining that he is the one who built Meat Alexandria's cryogenic sleep device.  Meat said it was necessary in order for him to help the New Generations in the future to come.
He reappears during the Kajiba no Kuso Djikara Challenge arc, where he chastises Meat for neglecting his duty towards Mantaro Kinniku and the Muscle League.  It is revealed he is the father of Bone Cold.  He wishes his son would lose the match to Mantaro, as he hopes it will make him realise that an evil path will not bring him satisfaction, and he hopes Bone Cold will be redeemed as he redeemed himself.  It is revealed that Kinkotsuman beat his wife, causing her to abandon Bone Cold when he was just five-years old, and he beat Bone Cold continuously until Bone Cold ran away at the age of eight.  Kinkotsuman catches Bone Cold after he falls from the ring once defeated, and offers Bone Cold money to kill him, as he hopes to atone for his sins of abuse - Bone Cold refuses and finally realises the error of his ways. 
Speech and Quotes
- Laugh: Muhyohyo~ (ムヒョヒョ～)
- First Line: "Indeed, I am Sharekoube, a.k.a Kinkotsuman!" (いかにも ぼくはシャレコウベ通称はキン骨マンだ! Ikanimo, boku wa Sharekōbe tsūshō wa Kinkotsuman da!)
- Kinkotsuman usually adds ~dawasa (～だわさ) to the ends of his sentences.
- 1,000,000 Yen Quiz Winner
- Kaiju Corps Leader
- Shame of the Universe (宇宙の面汚し, Uchū no Tsurayogoshi)
- Tragic Tiny Insect (悲劇のイジケ虫, Higeki no Ijike Muchi)
- Win/Loss Record (Singles)
- X Kinnikuman (Atomic Drop)
- Hobbies: Creating Kaiju, Foiling Kinnikuman
- Submitted by: Kōichi Mori (森孝一) of Chiba Prefecture
- Theme Song: "Kinkotsu Elegy" (キン骨エレジー) by Issei Futamata