Martial King's Retired Life - Chapter 145Book 14:

Spend life energy to infuse martial arts, and you can perform unlimited deductions.

Shen Yi’s mortal body only has a lifespan of less than a hundred years. Fortunately, he can gain his remaining lifespan by killing demons.

In the troubled times where evil spirits are everywhere, the long sword is revealed, causing the liver and gallbladder of these creatures who have lived for thousands of years to burst!

From [Eagle Claw Technique] to [Eight Desolations Splitting Heavenly Hands], from [Demon Subduing Fist] to [Golden Body Prison Suppressing Dharma Appearance]!

Shen Yi occasionally ponders, how come this lifespan is getting longer with more use?

He put the sword into its sheath, raised his eyes to the sky, and heard that there was a Jade Palace above the clouds. It was filled with thousands of saints, each of whom had experienced endless years.

This time I came to heaven just to borrow a million years from the immortals to prove my path to immortality.

- Description from novelbuddy

In a future timeline, the earth was visited by a species known as the Slarkovs.
Having lost their home planet and in search of a new one, earth was the next habitable planet for them.

Humans and Slarkovs made a deal with each other in return for the Slarkovs living on earth.
The Slarkovs traded their technology and knowledge for a new home.
They were similar to humans except for some of them who had slight differences so fitting into the society wasn't a problem.
Over the years Slarkovs and humans began to mate with one another and reproduce offsprings.
This in turn created a new species known as the mixed-blood.
Centuries later mixedbloods could tap into their bloodline and perform unimaginable feats.

Gustav born into an age where bloodline determines everything, struggles to fit with a useless bloodline.
His bloodline only grants him the ability to change his hair color, destroying his hopes and dreams for a great future.
His fate is turned around when an unexpected situation leads to him finding a system that grants him the power to unlock and upgrade bloodlines by completing quests but he's baffled by two quests with a five-year deadline. Success will grant him unimaginable rewards...
But only one thing awaits him if he fails... Death!

Follow Gustav on his interesting journey filled with unprecedented adventures, danger and death, maybe?

Officer, if I told you this just was a “Healing-type Game,” would you believe me?

The world had changed when the System arrived, alongside the Cataclysm that filled the world with monsters. The technology was gone, replaced by classes and skills that allowed the people to fight back. When Devon ended up as a Blacksmith, a class that didn’t grant Intelligence, he had to face the reality, that his old career that he loved - mathematical sociologist - was over. Instead, he had ended up as yet another discarded member of the production class, overshadowed by the existence of the System Shops to the point of total marginalization. But, what if all he needed was to reapply his scientific thinking to the System...