Billionaire's Secret Twins and Rebellious Wife - Chapter 10 - 0:

The day dungeons appeared on Earth, everything changed! From ordinary beasts to monstrous ones, attacks were common throughout the globe, and no one was safe.

After countless studies using these beasts as subjects, Humankind developed a serum capable of awakening incredible abilities in humans, leveling the battlefield.

With the serum came heroes and villains, those who wished to use their powers for good or bad.

The Garmony Upper School was a place for the elite with the sole purpose of creating heroes to fight the villains and explore more of the dungeons after the beast attacks increased for no apparent reason.

Damian Romero, a youth who received the serum after turning 18, yet got no unique ability. It was not uncommon for one to not receive power, but it was still a blow to one's pride.

He went rogue after the news, drinking alcohol and having a good time with women, and it was at that moment, when he was putting his toy to play, he got a surprise.

[All-in-One System Unlocked]

Damian's unique ability was a system with multiple functionalities, but after he studied it, it seemed this system worked with a different type of coin called Erotic Coins!

Improve his body? Buy any item or unique ability from his system's store? All Damian needed was Erotic Coins, and he knew how to earn them!

An ultimate warrior, the one and only Alchemy Emperor, Ling Han, died in his quest to achieve godhood. Ten thousands years later, he, with the ‘Invincible Heaven Scroll’, was reborn in the body of a young man with the same name. From then on, winds and clouds moved as he set himself against the uncountable geniuses of this new era. His path of becoming a legend has begun once more. Of all eras underneath the heavens, I am the strongest!

- Description from Novelupdates

“Transmigrate as the Final Villain of the novel...” Ark stared at his reflection in the mirror he held. It was Theos Von Fallen, the final villain of his favorite novel.Although he was the final villain and the strongest in the novel, he was killed by the protagonist and his harem in the finale.[Ding. The Heroine Snatching System has started] Ark gave a crooked smile when he read the system message in front of him... “Exchange!” he shouted, unwilling to accept the fate they had in store for him.Trapped in the world of his favorite novel as the most “evil” and powerful villain, Ark, now Theos, will use his knowledge as a fan obsessed with the novel to take away all the protagonist's opportunities.Whether he can become the focus of the whole show or whether a script will dictate his fate, he will decide! He will live as a true villain who doesn't care about anything but his life and his loved ones.

He never performed well in either middle nor high school, and even after becoming an adult, he never worked. Be it morning, noon or night, he only played an online game. For him, being the world’s number one rank, playing that online game, was his very reason for living.

One day, his account was hacked and his character deleted. Restoration was impossible. Nothing that could be done. The number 1 rank that he literally spent his life to attain and to defend was now lost. Filled with despair, he turned to suicide.

When he opened his eyes again, there was the online game. No, the world itself looked similar to the game. He had been reborn as the extra character of the premium avatar he created in the past, but left untouched.

The former world’s top, was reborn in a world that looked like that online game. That was the beginning of his extraordinary legend.

A knight, a cat, a dark elf, and so on. Together with several unique companions, his training to regain his “world’s first rank” now begins.