Aureole Omega

Lastborn of Pleiades is a member of the "Pleiades Seven Sisters", the battle maid squad of the Great Tomb of Nazarick.

Background
The Lastborn of Pleiades is the leader of the "Pleiades Seven Sisters" system. She is the only human NPC of Nazarick and possesses eternal life. Her name and other detailed information are unknown.

Chronology
In Volume 6, Ainz switches the Pleiades from the Six Stars to the Seven Sisters system of organization. Yet Ainz does not allow the Lastborn to move from her current position and thus Yuri Alpha becomes deputy leader.

Trivia

 * Solution slightly respond to Sebas and Shalltear's talk about the 8th floor of Nazarick. As details of the 8th floor is mysterious even to Floor Guardians, lastborn of Pleiades might be located in the 8th floor.