The Demon Sword Master of Excalibur Academy, Vol. 7 (light novel‪)‬

An unexpected invitation to the prestigious Holy Sword Blade Dance Festival sends the members of the eighteenth platoon on a trip to the First Assault Garden—Camelot. It’s hardly a relaxing trip for the group, though. The First Assault Garden is home to the Phillet Company, and Elfiné is determined to uncover more about its mysterious Demon Sword Project. To that end, she asks for Leonis to help her infiltrate a massive casino. Naturally, matters of espionage are no trouble for the Undead King, but things get more complicated when Veira arrives in a frenzy. Someone has managed to take control of the Dragon Lord as well as another Dark Lord...