Ai Asato

Born in New York. Daughter of martial artist Asato Ban, Ai is an expert of many forms of martial arts and used to be a Muay Thai champion. She used to be male but decided to change her sex after falling in love with her coach, who left for another country before Ai could express her love. Her old name is Ryuji. She fell in love with Ryotsu because he looks a lot like her former coach. She works as a traffic police in Katsushika Police Station in order to see Ryotsu often. She gets jealous easy and beats up Ryotsu when she thinks he is seeing other girls. In the manga version, she is transformed into a real woman by magic.