Skeleton Evolution: who was summoned by the Goddess is a Manga/Manhwa/Manhua in (English/Raw) language, Action series, english chapters have been translated and you can read them here.
Jiang Cheng was reborn in the game world, and he transformed into a skeleton as he was summoned by a beautiful witch with Skeleton Technique! This kind of skeleton is one of the strongest characters in the game! Fortunately, it has an infinite evolution system! He was a god level skeleton in the game world, and he defeated many other players.