Snowball Earth

Snowball Earth (大白球) is the residence of Cocytus.

Background
It is located on the Fifth Floor of the Great Tomb of Nazarick. There seems to be a constant blizzard in effect throughout the area's terrain, leaving nothing but some snowstorms trailing at its wake. Snows are always falling on the area's surroundings nonstop.

The snow driven by the blizzard went in all directions, obscuring all vision and covering up footprints. This was to waylay any intruders, but under normal circumstances the weather on the Fifth Floor was not so bad. The clouds which covered the sky would only dispense scattered snowflakes.

The Emissary of the King Arc
A Death Knight paid a visit to Cocytus' domain at its summoner's orders to learn of the desires of all the Floor Guardians.

The Two Leaders Arc
Mare Bello Fiore journeyed there to deliver a secret memo from Ainz Ooal Gown. However he learned that Cocytus was not home but in the Great Lake region supervising the Lizardmen Alliance.

Layout
Cocytus' home resembles an overturned vespiary, surrounded by six floating pillars of ice, where reside the Frost Virgins. The walls, ceiling, and furniture seemed to be made out of ice. This was probably an artistic decision. Aside from that, it wasn't much different from a regular home. However, it was big enough to include a conference room. It was big enough that Cocytus could swing his swords without a problem anywhere in the interior.

Trivia

 * Cocytus' home was designed for fighting that takes place indoors.