Konosuba: An Explosion on This Wonderful World! Vol. 1 (manga)

Crimson Magic Clan members Megumin and Yunyun are at the top of their class, but they still have a lot to learn. Yunyun's begun learning advanced magic, but Megumin has gone down a different path-the path of explosion magic! Despite being warned of its limited usefulness, Megumin believes explosion magic is the way for her to become a great, voluptuous wizard, and she won't be convinced otherwise!