The Demon Sword Master of Excalibur Academy, Vol. 6 (manga)

After completing the mission at the abandoned city, it-s time for the eighteenth platoon to take part in the Holy Light Festival, jointly held alongside the Sixth Assault Garden. Their event of choice? A haunted caf-It-s not all fun and games, however, as Nefakess-s dark influence begins to creep upon Riselia-