This anime shows promise. It’s a type of isekai layered inside another isekai setting. A king who was successful in war dies and is reborn into a different, more traditional fantasy world. He keeps all his memories, possessing the mindset of an adult but trapped in the body of a young boy. While his mature mental state has greatly aided him in grasping and practicing magic, there’s still a considerable amount to discover, dangers facing those close to him, and challenges to his established routines. Adding to these difficulties are individuals who want to manipulate him, and if they can't, they intend to remove him from the picture entirely. The narrative centers on the question of whether he will be able to achieve the tranquil existence he always desired while ruling in his previous life.

Source on TMDB