The Knight King Who Returned With a God - Chapter 188:

Zou Liang, an otaku with a passionate interest in a fighting game came into a world governed by the beast tribes.

There the ones with high martial ability were respected.

Extreme beauties were a little silly.

This guy felt depressed. Such a crazy really could force a civilized people like him to turn crazy!

Scoundrel Zou began his unrestrained and destructive journey in the Beast God Continent.

Rules? There are no rules!

Principles? His actions defined the principles!

Occupations? Occupations were as unimportant as fleeting clouds. What he sought was omnipotence!

In a different world, Zou held the same passion.

This is a story of a nobody becoming the great conqueror—step by step—as a human, filled with touching emotions, explosive anger, and hot blood forever!

- Description from Novelupdates

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?

Finding himself in an Last Airbender without an airbender around, a transmigrator waterbender goes on an adventure to stop the worst from happening to him.