Beast King Mekongawa

Beast King Mekongawa (獣王メコン川) is a guild member of Ainz Ooal Gown, and regarded as one of the Forty-One Supreme Beings by the NPCs of the Great Tomb of Nazarick.

Background
Other than YGGDRASIL, Beast King Mekongawa also plays another DMMO-RPG called Aberage with Nishikienrai together.

Main Equipment

 * Ring of Ainz Ooal Gown: It allows the user to freely teleport between every room inside Nazarick. Every member of Ainz Ooal Gown was required to wear this ring.

Nishikienrai
They both played a game called Aberage. When Beast King Mekongawa heard that Nishikienrai was among the upper ranked players in the game with the title of Violet, Beast King Mekongawa thought about quitting the game as he was only in the Green rank. Nishikienrai encouraged him to not quit the game and said they should group together to play in the next time.

Quotes

 * (To Nishikienrai): "Ehh?! What did you say? Doesn’t that mean you’re a super top-class player? I’m just a Green. Maybe I should quit Aberage"