Kyouko is Sasaki Kenji's girlfriend, and a protagonist in A.D. Police: To Protect and Serve. She is not a member of the A.D. police however.

The two met when Kenji saved her from an attacking Boomer. Kenji keeps his relationship a secret since he doesn't want to appear weak in front of the other members of his crew. It is only around Kyouko that Kenji's emotions come to the surface. She usually plays her violin for him after he is finished solving difficult cases since it brings him some measure of peace.