Mastema

Devil Mastema (マステマ, "Masutema") is a fictional character in the Manga series of Shaman King.

About
Devil Mastema is a demonic spirit that Lyserg Diethel fought during his training in hell with Pascal Avaf 's guidance.

Anime/Manga Difference
Devil Mastema is a manga Series only character and never appears in the Anime Series.

Trivia

 * Lyserg's strongest over Soul - O.S. Mastema Dolkeem, is named after it.