Roper

Ropers (ローパー) are a heteromorphic race of beings who are a variant of the Roper race from the YGGDRASIL.

Abilities
According to the Narberal Activity Report, a Roper's fluid is some kind of powerful secret drug.

Trivia

 * Ropers are officially introduced in the Light Novels in the Overlord Bonus Volume.
 * In the Narberal Activity Report released in a special edition pack, one of the Five Worst is described as a Roper.