List of characters in the Camp Half-Blood series
Skeleton - Skeletons were used by various people like Hades. In "The Lightning Thief," Hades had skeletons in army uniforms guarding his palace. In "The Battle of the Labyrinth," Nico manages to employ them as part of a ritual that will enable him to call the spirit of his sister to speak with her. In "The Last Olympian," Nico and Hades manages to bring a bunch of Skeletons to help fight the Titans. They are later seen constructing a cabin at Camp Half-Blood that is dedicated to Hades.