9th Class Sword Master: The Guardian of the Sword Manga

A brief description of the manhwa 9th Class Sword Master: The Guardian of the Sword:

After the “War of Trust,” which was waged to defend mankind from the forces of “corruption,” Karil MacGavern, a Sword Saint, must deal with Oliven, his close friend and the emperor, betraying him. Karil returns to the past after killing the emperor to make things right. He is now armed with both a sword and magic, giving him the strength he lacked in his prior existence. He is standing at the fork of two highways, wanting to alter the future.