Spartoi

Spartoi(スパルトイ, Suparutoi) are the spirits of Theodoros Alogospoulos

About
They were Spartan skeletons. Just 8 of the 300 Spartans, that died fighting against the one million strong persian army at the battle of Thermopylae, were chosen by Theodoros to become his guardian ghosts. Each of their weapons were antiques, and their skeletal structures were imported samples.

Anime/Manga Difference
They only appear in the manga