Doctor Doofenshmirtz (Nimnul's partner-in-crime, after a failure mission against Xanatos, Doofenshmirtz turned against his former employer, knocked out by Ibsen's mechanical hippo, to his apparent demise)
Valina (Recruit of the Skeleton King, slain by Madam Mim, on the second Battle of China)
Jack Spicer (Former Recruit of the Skeleton King, fate unknown after the second Battle of China)
Wuya (Jack Spicer's assistant, and the Skeleton King's recruit, retreated, during the Second Battle of China, joined forces with Mok and Aku, in the events of the Third War)
Valmont (Emissary of Shendu, retrerated, during the Battle at San Francisco, became gang leader of the Third War)
The Dark Hand (Enforcers of Shendu and Valmont, retrerated, during the Battle at San Francisco, became gang leaders of the Third War)
Shendu (Demon Sorcerer, bound to the will of the Skeleton King, slain by Mozenrath, on the second Battle of China, spirit found in the Netherworld, along with his brethren)
Negaduck (Former leader of the Fearsome Five and the New Fearsome Five, assimilated into the Skeleton King's Alliance, defeated in the Battle at San Francisco)
Tiburon (Hired Assassin, disappeared into the sea, after an encounter with Drago)
The Skeleton King (The creator of this faction that waits for the right time to strike against The Gems)
Emperor Zurg (Former ruler of Planet Z that was forced to retreat from his home after the attack of The Gems,joined the faction to help The Skeleton King with his ultimate goal,was eventually sent into another dimension)
Lord Dominator (Partner-in-Crimme with Zurg that remained loyal till the end)
Warmonga (Former bounty hunter of Planet Z that now became the bodyguard of Lord Dominator)