Nobody knows of Nina's past, just that she was kidnapped by assassins when she was young. She trained to become an assassin with other young children, until a man called Sergay Wang came to kill the assassins. Sergay sees Nina, and decides to adopt her. Nina trains in Garderobe from then on, to become Nagi's (Sergay's master) otome. She grows to love her stepfather more than loving a father, and is jealous when she finds that Sergay loved a woman called Rena Searrs from a photo album.
When she first meets Arika, she is angry at Arika for embarrassing her. This is because Arika tried to catch a drink from falling and landed on Nina instead. Nina fell down, showing the inside of her skirt, and she felt embarrassed in front of other people who were there, for example, Sergay. It is her dream to please Sergay and so she pretends that her dream is to become an otome, because Sergay would be proud.