Demon Dragon Mad God - Chapter 206 - 207: The Southern Barbarians Invade

In a world of power struggles and betrayal, A hero was once a loyal warrior who dedicated his life to helping his childhood friend ascend to the throne. Through blood, sweat, and unwavering devotion, he paved the way for his friend's reign—only to be betrayed the moment his goal was achieved. His life was cruelly stolen, but fate had other plans.Instead of death, he awakens in his childhood once more, armed with the memories of his tragic fate. This time, he will not be the loyal shadow of a false friend. This time, he will seize the throne himself.Yet, this is not his story.Our true protagonist is an ordinary man who finds himself reincarnated into this world—not as a hero, but as an extra. A mere background character destined to meet a tragic end, a third prince whose death will serve only as fuel for the true villain's rise. Slated to become an undead knight under the fourth prince, the last and most terrifying villain of this dark tale, he must now defy fate itself.With knowledge of the future and a world filled with scheming nobles, ruthless warriors, and an impending catastrophe, can this forsaken prince change his fate? Or will he meet his destined end, only to rise as a pawn in the villain’s grand scheme?A tale of revenge, survival, and defying fate begins now.

It was only after Su Yayan's death that she realized that she was a malicious cannon fodder female character who became a scapegoat in a Mary Sue story.

Yo, Hi! I’m Frank, I made a deal with a demon to pay me some money for receiving a guest for a few days every week.
I had no idea about what I have done.
On May 1st, Conan ‘the God of Death’ came to my house. I was forced to let him in and we get involved in a criminal case.
On May 8th, Bruce Wayne ‘Batman’ came to me. I was forced to follow him to fight crime.
On May 16th, Hannibal Lecter, The Silence of the Lambs, came to my home. I can only say that I really can’t stand my guests.

- Description from Novelupdates

A world where one’s life was decided by one’s talent called Gift.
The main character Erio Scarlet who was born in the house of influential noble family that had produced a lot of Holy Knights manifested a suspicious gift Incubus in the conferment ceremony. Furthermore the skill attached to that Gift was only one embarrassing skill called Peerless.

Erio was banished from the city because there was no way his indecent existence could be permitted in a family of Holy Knights but……somehow he went through an amazing growth when he dealt with his horniness though!?

In addition when his childhood friend who was bestowed with the Gift Sacred Knight chased after the main character because of her love for him reverse ra-……did it with him, a lot of powerful indecent skills showed up and on top of that they even got bound by Master-Servant contract……!?

This was the indecent heroic tale of the boy who was gifted with indecent Gift rising in the world while [getting along] with a lot of girls.