Bored Gamer in Other Worlds - Chapter 145

At the Tristain Magic Academy, her classmates call bumbling witch-in-training Louise Francoise le Blanc de la Valliere “Louise the Zero.” During an important coming-of-age ritual, when each student must summon their own witch’s familiar, Louise confirms her classmates’ opinion by accidentally conjuring up a normal teenage boy from Japan. Whether the two of them like it or not, the laws of magic bind them as master and servant forever! A hilarious novel with romance interwined.

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?

The older young Lisko woke up and found that he had become an American. He took over his father’s ranch and began to live in the United States.

- Description from novelbuddy