The Demon Sword Master of Excalibur Academy, Vol. 8 (light novel) — Yu Shimizu

The Holy Sword Dance Festival is fast approaching, and while Riselia and the other girls of the eighteenth platoon are training hard, Leonis is still missing. He and two other Dark Lords have been spirited away to some strange dimension ruled by Voids and are forced to search the desolate landscape for a way home. Meanwhile, the sinister forces behind the D Project plot to bring Camelot to ruin. A world apart, Riselia and Leonis desperately wish to see each other again, but will they survive long enough for a reunion?