User blog comment:AdrianC385/Skeleton King/@comment-33205717-20180414124443

Joker and Ozai-All 3 are Voiced by Mark Hamill

Horned King-Both rule the Dead,Skeleton King's New Form looks somewhat similiar to Horned King

Papyrus(Underfell)-Both are Skeleton Warriors

Darth Vader-Both are Tragic,Both have a dual personalitie,Both are father of the Heroes(IF Skeleton KIng is the Father of Chiro since one of the episodes,he has Chrio's Toys),Both are fallen Heroes,both use the force,both are brainwashedBoth are Idolized by Villains(Valeena and Kylo Ren,)Only differenece is Darth Vader reformed,if the series had not ended,Skeleton King would be killed by heroes again or he could return to his old self like Vader.