Upgraded hitter Conquest of the Issekayev (Konosuba)

What will happen to different stories if the place of the insecure OYAShs is taken by a person who has dreamed of power and a personal harem all his life? This is a story about a man who got a chance for a second life, and then for a third, fourth, fifth ... And he will stop only when there are no undefeated demon kings and girls forgotten by the OYAS in the multiverse. #By the way, if it's easy, look at my other fanfic The path to success is rebirth? and Immortal God of Chaos#