3-sizes: 85/56/85 cm
Kyouko is a half-alien idol known for playing the magical girl Magical Kyouko in her own TV show—one that Lala is obsessed with and regularly drags Rito into watching. She's got fire powers, which she can create and throw at will, and she eventually befriends Run after they work together on the show (Run plays a villain). The two hit it off and end up collaborating on music projects down the line.
When Run later asks Rito to be her date, Kyouko's perceptive enough to see through the act, though she's cool about it and wishes Run good luck anyway.
The most memorable thing Kyouko does in the series happens during an RPG world that Lala creates for Rito and his friends. Nana and Momo mess with Kyouko's in-game programming, turning her into the "Demon King"—a supposedly unbeatable boss designed to hunt Rito down and blackmail him into choosing between saving his friends and leaving Lala forever. To amp up the pressure, Demon King Kyouko threatens to destroy everyone if Rito won't confess his feelings for Lala. It's played for laughs, especially since the invincible Demon King gets taken out by a watering can that only Rito can use.
Kyouko is essentially a tribute to Kyouko Kirisaki from Black Cat, and they share the same voice actress across drama CDs and anime. Both characters even manipulate fire and are the same age, though otherwise their physical stats and birthdays don't line up.
Content compiled by AnimeList.moe from publicly available sources.