The Heroine is My Stepsister, and I'm her Final Boss - Chapter 1: Despair and Death.

Jiang Bai woke up one day and found with shock that he had transmigrated to a parallel world that is similar to Earth. There, he was granted a cheat system to help him forge the path of a tyrant in this new world. He was now stuck in this parallel world body, the body of a weak and cowardly person. Join Jiang Bai as he rose to the top in this new world!

- Description from Novelupdates

[Slice of life]

What would you do if you could copy abilities during an apocalypse?

Of course, you can only copy women's abilities by having sex with them and absorbing their coitus essence!

Jake Mystro, a determined and strong-willed teenager without an ability, was frowned upon and disdained for being powerless, as his body even rejected artificial abilities. Yet, that didn't bother Jake or make him sad, rather, he supported himself with the help of beast gears to avoid being bullied.

However, on a particular day, Jake got tricked into awakening his Vampiric powers, but the process left him in a life and death condition. Luckily, he acquired the 'Cuckold System.

[Ding!]

[You have acquired the Cuckold System]

[The Goddess of lust has acknowledged your strong will and determination]

[You have become a dedicated follower]

[By stealing other people's women you shall become stronger]

“I shall not become the follower of anyone! I will also conquer the goddess of lust! Mark my words!”

[Fufufu.....you have balls of steel, you know?]

Let's follow the journey of Jake Mystro as he embarks on the journey of doing perverted tasks and becoming men's worst nightmare.

Until the time of him becoming the master of the lowest rank in the order of rankings, the lonely side of his life without luck was changed.

In the northern part of the world, a long-standing battle between various races and the demon race has finally reached its end. The Demon Lord, a figure with black hair, red eyes, rules from her obsidian palace, having repeatedly defeated the Goddess, the strongest being in the world. However, she refrains from killing her, knowing she will only be reborn to lead another attack.As the goddess kneels before her, badly injured and helpless, the sounds of explosions echo outside, signaling the imminent victory of the alliance. Despite her immense power, the demon lord acknowledges the demon's overall weakness compared to humans and the Alliance. The development of fighting energy and mana has allowed ordinary humans to fight demons, leading to the demon army's defeat.Aware of the Alliance's intent to enslave the abyssal demon, the Demon Lord decides to cast a forbidden spell that will cost her life. As the Alliance forces storm the palace, they hesitate upon sensing the spell's energy. The Demon Lord vows to resist and be reborn to save her people.Meanwhile, the goddess reflects on the demon lord's past treatment of her and acknowledges her respect and dedication to her people. As the demon lord prepares to cast the spell, the goddess asks if she can abandon her plan and live freely. However, demon lords are duty-bound to restore the demon race's glory and protect her people.Understanding the demon lord's resolve, the goddess readies her sword, intending to clash with the demo lord's forbidden spell. The resulting explosion creates a mushroom cloud, marking the end of the conflict and the start of a new era. The Demon Lord and the Goddess become historical figures, their stories occasionally told.