Isekai Cheat Sensou

Isekai Cheat Sensou (異世界チート戦争, lit. "Cheat Magician War in the Different World") is a light novel series by Yukiya Murasaki with illustrations by Choko Fuji.

Plot
A certain male met the end of his life in an unintentional manner. And upon reincarnation, he was faced with another world. Given the name Setsuri, he worked until he grew to be known as a genius. Within these peaceful days....he was informed by a girl named Mau, that his fate was to fight...