Shi ni Modori, Subete wo Sukuu Tame ni Saikyou He to Itaru

Eric has had a hard life. At the age of 16, his village was overrun by monsters, who killed his friends and family. He soon became a soldier, but failed to save the life of the woman he loved. In the end, he died on the battlefield, surrounded by the bodies of those who he couldn’t protect.
When Eric wakes up, he finds himself in a baby’s body. Realizing he has been reincarnated, he quickly wonders what is going on before he gets another shocker: the man and woman who are raising him are in fact his previous life’s parents!
That’s right - Eric was reincarnated, but as himself. No alternate worlds, no skill trees, just his memories sent back to the moment he popped out of his mother. Armed with the knowledge of his past self, Eric vows to save everyone now that the universe has pushed the reset button for him.