Sousei no Tenken Tsukai

Chou Sekiei previously lived as the undefeated war hero Kou Eihou. A thousand years later, he seeks a peaceful life as a civil official. However, he still possesses unexplained combat abilities. As a child, he was adopted by a famous general and trained with Chou Hakurei, known for her skill and beauty. He has also become involved in rescuing a young, immature merchant prodigy. When the nation of Gen invades, triggering war, Sekiei must set aside his desire for peace and use his skills again. Alongside his friends, he faces the challenge of defending their homeland.