Reign of the Seven Spellblades, Vol. 4 (light novel) — Bokuto Uno

The clashing of blades echoes in the depths of the labyrinth, and Oliver takes his first steps onto the path of blood. As he plots his vengeance from the shadows, though, other students are putting their own schemes into motion. Despite Oliver's best attempts to remain obscure, he and Nanao have attracted the attention of their classmates with their magical prowess. “Who is the strongest first-year?” they wonder. Well, there's only one way to find out -- a battle royal�"style tournament!