Doryoku Muso no Tensei Exorcist

No lineage, no talent, but the strongest exorcist. Stabbed by a random assailant, he is reborn into a world infested with demons. The orphaned protagonist begins his second life at an orphanage run by a noble family that produces exorcists - those who protect the human world from demons. He has no superior lineage and no talent. But to avoid death and protect his beloved master, the protagonist continues to work hard - and before he knows it, he becomes the strongest. This is the story of how the protagonist, once looked down upon as an ordinary person, becomes the most feared exorcist and makes a name for himself in the exorcism world.