Ghast

Ghasts (腐肉漁り) are a class of higher-class undead.

Appearance
No word of it's exact appearance has been directly mentioned as of yet.

Abilities
The top species of undead that are stronger than zombies and skeletons.

Trivia

 * In the Web Novel, it was said that Rigrit Bers Caurau could summon and control 20 Ghasts. Whereas Fluder Paradyne could only summon and control 10.
 * During the invasion of Nazarick, Hekkeran Termite tenth group of monsters that he fought were a pair of ghasts.
 * Ghasts are a race of fearsome humanoids from H. P. Lovecraft's work.