The Retired Hero is an Extra - Chapter 9 - : Confused Ziva

After all, transmigrators of this era were no simple matter. Some became slimes, others turned into treasure chest monsters, and some were even reduced to mere skull--such things were all commonplace.It was nothing more than playing a villain, Shiayar didn't care. Wasn't it only natural to pay some price to become stronger?[Destined Great Villain System][“Let this world feel the agony!”][Newcomer Mission: Let the young and naive Grand Duke's daughter of the Azure Garden Dukedom, Miss Silvia, experience the betrayal of her loved ones and, amidst the pain and despair, complete her transformation and rebirth.]

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

“My name is Shun Satsujin. I'm an orphan… and someone who died only to be reborn into a world filled with fictional stories I once knew.”I expected a cheat ability—something powerful or overpowered. But all I got… was an intense exercise method called Herculess Method and a challenging life.Now, I'm just trying to survive and stay on track.That was the plan—until I enrolled in Shuchiin Academy.And suddenly, I found myself surrounded by girls from anime I used to watch.One by one, they started getting involved with me.

After accidentally falling, she actually finds herself bound to a Second Female Lead Counter Attacking System!