DRAGON LORD

This is the prequel to the story Chronicles of a Halved Soul. The main character Chayot after dying discovers that when he reincarnates, he retains all the knowledge he learned in his previous life. After several deaths and rebirths in alternative worlds, he eventually remains in a specific timeline on an island citadel.

As an advanced soul in a medieval world, he slowly builds a world where he is able to extend his lifetime, by transferring his soul from his old physical body into a newborn physical body not yet claimed by a new soul. A dynasty is quickly created where he remains on the island.