Reincarnated as the Archduke's Son

Story:

A mercenary captain dies on the battlefield, having never advanced in life because of his lowly bloodline. When he opens his eyes again, he learns that he has been reincarnated as the third son of an archduke—now blessed with the prestigious family, status, and innate talent he always dreamed of. With the combat experience of a former mercenary commander and the advantages of noble birth, he decides there’s only one path left: climb all the way to the top. Thus begins his bold, “from ex-mercenary to high noble” life, as he shakes up aristocratic society while living as the archduke’s third son.