Satsu is a fictional character created by Joss Whedon for Buffy the Vampire Slayer Season Eight, a comic book continuation of the television series Buffy the Vampire Slayer. Introduced as one of the strongest Slayers, she has a close relationship with her mentor Buffy Summers. Satsu develops romantic feelings for Buffy, and the two have a brief sexual relationship. She becomes the leader of her own Slayer squadron in Tokyo, and forms a friendship with fellow Slayer Kennedy during her performance review. She also makes a minor appearance in Buffy the Vampire Slayer Season Ten.

Buffy the Vampire Slayer Season Eight is a comic book series published by Dark Horse Comics from 2007 to 2011. The series serves as a canonical continuation of the television series Buffy the Vampire Slayer, and follows the events of that show's final televised season. It is produced by Joss Whedon, who wrote or co-wrote three of the series arcs and several one-shot stories. The series was followed by Season Nine in 2011.