The Mushoku Tensei: Jobless Reincarnation.

  Despite being bullied, scorned, and oppressed all of his life, a 34-year-old shut-in still found the resolve to attempt something heroic—only for it to end in a tragic accident. But in a twist of fate, he awakens in another world as Rudeus Greyrat, starting life again as a baby born to two loving parents. Preserving his memories and knowledge from his previous life, Rudeus quickly adapts to his new environment. With the mind of a grown adult, he starts to display magical talent that exceeds all expectations, honing his skill with the help of a mage named Roxy Migurdia. Rudeus learns swordplay from his father, Paul, and meets Sylphiette, a girl his age who quickly becomes his closest friend.