Tsuareninya Beiron
Tsuareninya is a maid apprentice of the Great Tomb of Nazarick under Sebas Tian's supervision. She is the older sister of Ninya. She is also under the protection of Ainz Ooal Gown due Ainz wanting to repay a debt to Ninya. She has very low self-esteem and tends to dislike humans due to their treatment towards her, and is afraid of going outside due to the threat of recapture. She is greatly attracted to Sebas and trusts him even though he has previously attempted to kill her on direct orders from Pandora's Actor shape-shift form of Ainz. She now prefers to stay away from human civilization. Tsuareninya was very close to her younger sister as she knows various things about her. Ninya mentioned that her older sister was taken by a noble but that she still doesn't know what happened to her. It became clear that she was sold into slavery. At some point she was sold to a brothel, and after severe abuse, was about to be disposed of when Sebas encountered and saved her. (Source: Overlord Wikia)