凡人転生の努力無双 ～赤ちゃんの頃から努力してたらいつのまにか日本の未来を背負ってました～

Synopsis

Itsuki, a boy killed by a random attacker, is reincarnated. He is reborn in Japan, a country where monsters called "demons" exist—and into a family of "exorcists" who use magic to slay these monsters! Children of exorcists are easily targeted by demons, and if they are weak, they will be killed again. So Itsuki made a decision. To become strong—so that he would never die again. He practiced magic from infancy, aiming to become the strongest... and then he realized. "Damn... I tried too hard..." He's an ordinary person who became the strongest by trying too hard!? A fantasy of unparalleled power where he defeats demons one after another begins!