Becoming evil makes you ten times stronger, but becoming a demon gives you hundredfold strength - Chapter 468 - 359: Life and Death Decision, The Sword Sharpener_2

An unnamed 34-year-old Japanese NEET is evicted from his home following his parents' death.

Upon some self-introspection, he concludes that his life was ultimately pointless.

Walking down a street he intercepts a speeding truck heading towards a group of teenagers, in an attempt to do something meaningful for once in his life he manages to pull one of them out of harm's way before getting himself in the way of the truck and dying.

Awakening in a baby's body, he realizes he has been reincarnated in a world of sword and sorcery.

He resolves to become successful in his new life, discarding his past identity for his new life as Rudeus Greyrat.

“If you were the supreme master of the Dao of Immortals, revered by countless beings, able to glimpse life and death, and understand the destiny, what kind of woman would you seek as a partner?”Jiang Feng: “I would marry an eighteen-year-old.”“...do you want to die?”“I'd rather die to marry an eighteen-year-old.”

Rimu Dynasty, Kingdom of chaos. Demons were rampant, and it was difficult for people to live.

Gu Qing’an had not yet had the opportunity to appreciate his beauty upon transmigrating in this world, as he had to face the demon who targeted and devoured humans.

Fortunately, she had a system.

“I, Gu Qingan, have never been weaker than others. System, add it to me.”

……

Many years later, Gu Qing’an, standing on the frozen void, looked at the newly discovered strange world under her feet without any expression.

“Compared to human beings, alien existence is a demon,” she thought to herself.

“Then, are all creatures in this entire world considered demons?”

- Description from Novelupdates

An Individual from Earth finds themselves in the Shinobi World, equipped with a Scientific System. From that moment, he delved into scientific research far ahead of its time.