In YGGDRASIL, Grenbera Tuvegs were one of the monsters that spawned around the swamp area where the Great Tomb of Nazarick was located originally. It guards the unconquered Great Tomb of Nazarick against enemy players and NPCs if caught on sight trying to trespass into their territorial ground before reaching the tomb.
They look like bipedal frog-monsters.
Grenbera Tuvegs are monsters that have adapted to living in a swamp-like environment. In YGGDRASIL, their level can reach as high as level 80. The huge patch of wetlands littered with poisonous marshes were controlled by the Tuvegs, who are immune to poison. They had the ability to see through enemies using concealment techniques.
- The members of Ainz Ooal Gown avoided confronting this monster as they made their way to Nazarick.