The Heroine is My Stepsister, and I'm her Final Boss - Chapter 80: Slay

Imagine a system that would let you create any skill you could imagine. Being the best at whatever you dreamt of becoming.Felix, who thought his whole life would remain average and ordinary despite hating it gets an unescapable chance to encounter the Legendary Truck-kun. Knowing it was a chance to change his life, which was a repeat of struggle every day, he happily accepted his ticket to Isekai.Waking up in the body of a wounded boy in a fantasy world, the boy finds out that his fate seems miserable. After nearly experiencing something worse than death, he finally awakens the Great Skill Creation System.Creating skill after skill that lets him achieve his goal, Felix treads upon the darkest of secrets and conquers a myriad of worlds with his trustful comrades. Watch how he changes the fates of everyone and the universe on his mystical journey.

As soon as he crossed over, Su Mu came to another world.

In this world, there are warriors, qi refiners, and all kinds of terrifying ghosts and monsters!

A good rebirth simulator turned into a death simulator because it was too dangerous.

For him, death is not the end, but the beginning.

In the simulation again and again, thousands of demons have been derived!

The flesh and blood are put into the pot, divided and eaten, turning into a bloody skeleton.

He died in a wrongful battle, his body did not rot, and he turned into a dry zombie.

Introduce thunder into the body, turn extreme yin into yang, and transform into a fierce reggae.

Devouring demon souls, suffocating the sky, turning into an undead ghost car.

Some people become immortals.

There are also people who die into demons!

- Description from novelbuddy

Roy’s life was nothing special. The only thing commendable was the last few moments when he saved a mother and her child from a drunk driver.
…
It’s really an egg! Damn it, what kind of monster have I become? Did I fall into Hell instead of making it to Heaven??
Join Roy as he ventures through various worlds with the Custom Made Demon King System—a system that allows Roy to draw anything he can imagine and create it through exchanging souls!

You take up a student career.

Student career upgrade to lv.7

Acquired skills: primary school knowledge, junior high school knowledge, high school knowledge.

You take the college entrance examination,

You got a perfect score.

Your basic occupation has been upgraded to lv.9, and the job transfer system has been activated.

You change jobs to become a scientist, you gain R&D skills

You use research and development skills to get space fortress construction technology

You use R&D skills to gain starship technology.

You are invincible.

- Description from novelbuddy