The Demon Sword Master of Excalibur Academy, Vol. 9 (light novel) — Yu Shimizu

A TENSE REUNION!

The eighteenth platoon's bravery during the recent Void invasion has earned its members a private audience with Princess Chatres. While Leonis thinks this is an excellent opportunity to scout the elite Elysion Academy, Regina is not nearly as excited. The idea of spending time with her long-lost sister has her nervous, to say the least. Little do they know evil has not left Camelot. A massive tear in the sky revealing the home world of the Voids still looms above, and an old enemy of the Undead King plots revenge in the shadows below…