Yoko first and lastly appears in Episode #2 "The Terms of Stardom". Originally she's actor Yukie Tsukimura's assistant and understudy. Her overambition and egotism drive her to solicit Yukie's secret to success, the nightbreed Mariel. She becomes even more paranoid and egotistic with her new success, but is a very cool character.

(source: Absolute Anime)