Pleiades

Pleiades (プレアデス) is the combat maid squad of the Great Tomb of Nazarick. Its members originally only served as Nazarick's last line of defense, but Ainz has assigned them more tasks after the tomb was transported.

Background
The Pleiades is the combat maid squad of Nazarick, programmed as sisters. Unlike the other homunculus maids under the orders of Pestonya S. Wanko, the Pleiades members do not have any skills for housework and instead fight under Sebas's command as a final raid boss team right before the throne hall. All of them are women of unsurpassed beauty, each with a different type of appeal. After the teleportation to the New World, three of them are working outside of the tomb. This seems to be because they are amongst the rare NPCs from Nazarick who can easily disguise themselves as humans.

The Pleiades can be organized in two different formations. One is the "Pleiades Six Stars" and the other is the "Pleiades Seven Sisters". These formations can be switched by changing the leader to either Sebas or the Lastborn of the Pleiades. The "Pleiades Seven Sisters" activates in volume 6, yet Ainz does not allow Lastborn to move and thus, Yuri Alpha becomes deputy leader.

The Undead King Arc
Momonga orders the Pleiades to guard the 9th floor for possible intruders in the Great Tomb of Nazarick.

The Dark Warrior Arc
Ainz Ooal Gown choose Narberal Gamma to be his adventurer partner and infiltrate the fortress city of E-Rantel. It was part of his plan to become a famous adventurer, so that they can gain more information about this world.

The Bloody Valkyrie Arc
In E-Rantel, Shalltear Bloodfallen's task was to enslave any criminals, who knew martial arts or magic talent. Sebas Tian and Solution Epsilon have been ordered by Ainz to disguise themselves as humans, and gather information in the Re-Estize Kingdom. In particular, the roles they played were an elderly butler and a spoiled rich princess. As well in E-Rantel, Naberal stay at the inn and wait for Ainz's instruction, when he returned.

Strength
With all of them except Sebas being under level 65, the Pleiades's combat capability is quite low, considering the role they have been given. This is because the final defense line of Nazarick is actually concentrated on the 8th floor. The actual purpose of the Pleiades is just to delay the invaders, allowing more time for all the guild members to gather in the throne hall and greet the invaders like villains in fiction. Despite this, the low power levels in the New World make them equivalent to legendary monsters.

Known Members

 * Sebas Tian - Leader of Pleiades Six Stars System
 * Yuri Alpha - Deputy Leader
 * Lupusregina Beta
 * Narberal Gamma
 * CZ2128 Delta
 * Solution Epsilon
 * Entoma Vasilissa Zeta
 * Lastborn of Pleiades - Leader of Pleiades Seven Sisters System

Trivia

 * The dual organization of the Pleiades refers to two different meanings of the word "Pleiades". In Greek mythology, the Pleiades refer to the seven sisters, daughters of the titan Atlas, while in astronomy the Pleiades is a star cluster called the "Six Combined Star" (六連星) in Asia.
 * The homunculus maids of Nazarick think of the Pleiades as a kind of idol group, with CZ being the most popular among them.