Makeruna! Makendou Z

Sisters Hikari and Mai attend the same high school, where everything runs normally until their cousin Saya returns from an exchange year in the United States. Saya's return coincides with a laboratory accident that opens a gate to the demon world somewhere inside the school building. The demons pouring through are not something a school administration can address — they require the kind of response that magic kendo powers provide. The three girls take it upon themselves to find the demonic portals scattered through the campus, close them, defeat the demons that have already entered, and restore the school to a state where classes can resume.