Also known as: イスカ
Main villain of Isuca and the second title character, as she shares her name with Shimazu Sakuya's "true name" (this being one of several mysteries about her). She's a western mage who's out to get Sakuya's eastern-mage family. As Sakuya is to Shana, Isuca is to Hecate (Shakugan No Shana) -- they even wear similar Hats.