After Marrying a Vegetative Princess, I Went Crazy With Joy! - Chapter 255

[Host, host, I am the System, I can help you conquer the world and the witches with various personalities.]Xi Mu: Hmm... Isn't this an action game? When do we start slashing?[Right... This is an action game, but I suggest that the host also try to seduce the witches along the way, there are generous rewards.]Xi Mu: What rewards?[Of course, the perfect romantic experience!]Xi Mu: No need, I've already played through the romance plotlines. Now I just want to go on a rampage and speedrun the game.][...]

As a walk-on, he had been the mistress of his sugar daddy for three year. However, they only had met each other for a few times.
As a boss, his sugar daddy had tons of lovers.
The walk-on: The cake shop is the only thing I love in this world. Lovers? Never want one.
The boss: No problem. Nobody wants that.
Then, they fell in love with each other…
Shameless playboy x heartless rogue
1v1, this is not a decent love novel.

- Description from Novelupdates

A college student was returning home after studying abroad for several years when the end of the world happened. A dragon appeared out of nowhere and attacked the plane he was in, thanks to an incredible amount of luck and his quick-thinking, he managed to survive the plane crash only to get stuck on a tropical island. A weird system took over the world and brought monsters to Earth. While nations collapsed and the world as a whole was being destroyed by ridiculous monsters, Leon was stuck on a godforsaken island with no chances of being rescued. What will happen to him? How will the world change while he is away? Will he even manage to return? The story, all names, characters, and incidents portrayed in this production are fictitious. No identification with actual persons (living or deceased), places, buildings, and products is intended or should be inferred.

This is a world where a king is the most powerful.