地味な剣聖はそれでも最強です

Due to a divine mistake, Sansui Shirokuro meets an untimely death. To make up for it, he’s sent to another world. He wishes to be fawned over in classic I’m OP fashion, but when he tells that to God, he somehow ends up training under the hermit Suiboku… Five hundred years later, when he’s become a full-fledged hermit, Sansui stumbles upon an abandoned baby. He names the child Rein and ventures into the world to raise her… Thus, the hermit with a baby begins his parenting. (Source: Manga Mirai)