Aureole Omega

Aureole Omega (オーレオール・オメガ) is an Area Guardian of the Cherry Blossom Sanctuary and the leader of the "Pleiades Seven Sisters", the battle maid squad of the Great Tomb of Nazarick.

She is in charge of the Teleportation Gates in Nazarick and protecting the Staff of Ainz Ooal Gown in the Cherry Blossom Sanctuary.

Background
Aureole Omega is the leader of the "Pleiades Seven Sisters" and the Area Guardian of the Cherry Blossom Sanctuary that controls all the teleportation gates in Nazarick. She is the only human NPC of Nazarick that possesses an eternal life.

The Emissary of the King Arc
When Ainz sent out his Death Knight to interview each of the Floor Guardians, Aureole Omega noticed its presence in using the Gates. Seeing that the undead wasn't an enemy, she allowed it passage.

The Men in the Kingdom Arc
Ainz switches the Pleiades from the Six Stars to the Seven Sisters. While so, Ainz does not allow Aureole Omega to move from her current position and thus Yuri Alpha becomes temporary leader of the Seven Sisters.

The Two Leaders Arc
When Nfirea, Enri and Nemu were teleported to the the ninth floor during their visit in Nazarick, Enri saw a shower of pink petals, there was the vision of a woman in clothes which were white on top and red on the bottom.

Abilities and Powers
As an area guardian, she is in charge of overseeing all the teleportation gates in Nazarick. If an intruder attempt to use it, She will teleport or divert the intruders that using the portal to the isolation area of her choice. When Ainz switches the Pleiades from the Six Stars to the Seven Sisters System, she is now the leader of the Pleiades.

Ainz Ooal Gown
She is entrusted with the protection of the Staff of Ainz Ooal Gown in the Cherry Blossom Sanctuary when it is not in the possession of Ainz.

Trivia

 * There is an unknown female NPC in the picture of all 100 level NPCs in Nazarick. As the NPC's clothes is similar to that of miko (Japanese female shaman).
 * She is the original owner of the World Item in the 8th Floor and it was given to Shalltear Bloodfallen.
 * Her name is finally revealed in the bonus booklet of the Overlord Movie, The Undead King.