Mastema

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

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 does not appear in the 2001 anime series.

Trivia

 * Lyserg's strongest Over Soul, Mastema Dolkeem, is named after it.