The mother of Lotte. Mercelida is extremely promiscuous, even for a succubus. She once slept with a man from her harem while Lotte (who was 5 then), was in bed with her. This is slightly changed in the anime, so that instead of the man coming uncalled when Lotte was already in bed with her mother, he came when Astarotte was heading to her mother's room, so that her mother did not know she was there. The shock of this experience is identified as the origin of Astarotte's hatred toward men.
She is also the Mother of Asuha. It is implied that she has a liking for Naoya; she also keeps secret about the fact she is the Queen from Asuha, and regarding Lotte the truth about her older sister.