Siganeul Dallineun Swordmaster

He saves the future by going to the past! Ransen, the last prince of the Vanroa Kingdom destroyed by the Empire's invasion, sets out for a distant foreign land with the children of his retainers. Struggling to survive, he eventually becomes a Sword Master at a young age. But after an unexpected incident, he loses his strength and those around him are put in danger... To survive, he uses an ancient relic to travel ten thousand years into the past, where he gains a mysterious fortune and returns to the present to overcome the crisis. Yet the dangers continue to repeat, forcing him into time travel again and again. Amidst it all, astonishing secrets tied to the present begin to surface one by one.

(Source: Naver, translated)