Ken died (was killed) and given a second life in the body of the First son of an esteemed Dukal house of a Kingdom sandwiched in between empires. Instead of toiling away, waisting this life as well, and doing things he didn't enjoy Ken decides to spend this new chance doing the opposite.
Be it, making a harem, being a benevolent ruler, ar an evil one, helping he people, getting stronger, or doing as he pleases without repercussions, and blackmailing and maybe even worse. Ken will try it all and live life to the fullest. And maybe find a deeper purpose in life, other than sex and strength.