Almost nothing is known about the mysterious Skeleton Ki except from his own boasting comments and arrogant claims. However if he is to believed, than in certain criminal circles; he is one of the world's greatest thieves and has an enviable reputation from Samarkand to Sinkiang having stolen crowns off the heads of kings and swords out of the hands of hussars and highwaymen before they even realized it.
Apparently possessing the occult power to open any lock and bypass any security, Skeleton Ki was hired by AIM to steal a mysterious pyramid from Rand-Meachum Industries. Naturally Skeleton Ki found himself confronted by Danny Rand aka Iron Fist, the owner of Rand-Meachum for possession of the pyramid. Although physically defeated by the superior martial arts skills of the Iron Fist, Rand was confounded by Skeleton Ki's remarkable ability to defeat his security measures. Despite Iron Fist's best attempts, the mysterious thief was able to escape.
His career for the next several years remain a mystery but ultimately he was captured and sent to the Negative Zone Prison Alpha codenamed "42". When the prison fell under attack by Blastaar and his army, the prison personnel abandoned 42. Skeleton Ki arose among the prison population as one of the new leaders along with Condor, Arthur Nagan aka Gorilla-Man, and Bison as he used his occult powers to try and repair the portal to Earth.
Learning of the situation, Star-Lord of the Guardians of the Galaxy attempted to intervene as fixing the portal would allow Blastaar the ability to invade Earth. He failed to convince them and instead Skeleton Ki made a deal with Blastaar in exchange for his life, surrendering 42 and the portal to Earth.
Skeleton Ki was later brought before Blastaar and ordered to figure out a way to fix the portal or else Blastaar would kill him. However, when the Shadow Initiative took back 42, Skeleton Ki was arrested again and taken to the Raft where he was later shipped off to Seagate when J. Jonah Jameson had the Raft shut down.