Zentos already taught Kail how to be a magic swordsman. He has his memories from his previous life.
Remember, the scene we see isn't of Zentos and Kail in the past, it's the future to everyone here, the past to him.
Zentos and Kail became friends after the princess was slain and the kingdom fell.
Remember, the scene we see isn't of Zentos and Kail in the past, it's the future to everyone here, the past to him.
Zentos and Kail became friends after the princess was slain and the kingdom fell.
