The Rebirth of the King.
The most powerful king in the world finds himself in a strange new world... and a helpless infant body.
Aired 30/03/2025EP 1 - The Rebirth of the King.

2025
The Beginning After the End
After a mysterious death, King Grey is reborn as Arthur Leywin on the magical continent of Dicathen. Although he enters his second life as a baby, his previous wisdom remains. He begins to master magic and forge his own path as the years go by, seeking to correct the mistakes of his past life.
(Source: Crunchyroll)