The supporting character's harem is very normal - Chapter 249 Do you like this size?

In his past incarnation, Lu Xuan was the youngest Celestial Lord that the universe has ever seen!
An accidental rebirth brought him back to a thousand years before, where the Earth had just begun its spiritual reawakening. When he stepped onto the way of cultivation for a second time, he swore to rewrite all injustices suffered in his past life, and defeat all enemies that dare stand in his way!
Let invincibility be his cultivation and the path he treads. In this life, it is his destiny to be invincible!

There are a total of seven sins, and a revelation is made to a young man named Alex that he is destined to become a demon lord, more especially a demon lord of sin called LUST.

It's not like he can change that and because he always knew something about himself was different—not in a physical sense, well, maybe a little—and not in a mental sense—but rather because he is thrown into a demonic war that compels him to accept his new reality.

He was only aware of a difference in himself. Relating to him and the ladies who are drawn to him... Well, it was more or less like he was a magnet in front of all the girls, and all the girls were drawn to him like a metal.

[The criteria for unlocking the system have been fulfilled.][System synchronization with host commencing.][Synchronization complete. Congratulations. You have been given a chance to become the most desirable human in this world, just as you wished.]“This isn’t what I wished for.”[What seems to be the problem?] the voice asked, a hint of curiosity in her tone.“I asked to be the most desirable human, not a woman!” he exclaimed, frustrated as he cupped his newfound breasts.Sylvester Lancaster, a dedicated and kind-hearted unactractive policeman, often dismissed and treated like a doormat, snaps after discovering his newlywed wife in bed with his best friend. Consumed by rage, he goes on a violent rampage, only to realize the horrific extent of his actions when the blood cools—he has committed murder. Panicked, he attempts to flee but is struck by a car and meets his untimely death.However, death is far from the end. Sylvester awakens in a morgue, only to find himself in a bizarre alternate universe—trapped in the body of a stunning young woman named Cara Bolton.In this new world where Sylvester has transmigrated to, vampires, werewolves, witches, and other supernatural beings coexist in a fragile balance with humans, their uneasy peace marked by underlying tensions and hidden conflicts. Among the supernaturals, vampires reign supreme as the most dominant and influential. The system reveals to Sylvester that he now wields two new skills: the power to read minds and the ability to detect lies, skills inherited from Cara, the body’s former inhabitant who was a fairy.The system assigns him quests to complete, allowing him to level up and gain all remaining skills a fairy possesses. Many of these missions involves sex, manipulating and exploiting people, as well as infiltrating the vampiric council.