Itai no wa Iya nanode Bōgyo-Ryoku ni Kyokufuri Shitai to Omoimasu - Chapter 375

The formless ancient world was infested with despicable demons. They hunted and feasted on mankind, keeping the human civilization constantly in a weak and suppressed state.

During the first known year, a magical mountain descended into the world from the realm of the Gods. Carved on this enormous mountain was a message: ‘Heaven Prevails’…

After the Grand Descent, a name that was given to the descending of the mountain, the Three Great Sages made their ways to Mystic Mountain where they learned to harvest what we now call magic, establishing the Mystic Cults and eighty-one sacred shrines to help aid mankind with the cult’s mystic powers against the eternal fight to the death with demons.

- Description from Novelupdates

The world was at the brink of collapse. Humanity’s desperate battle against the Harbingers, monstrous alien invaders from another world, had raged for years, leaving cities in ruin and hope at an all-time low.Amid the chaos, Noah Eclipse, an eighteen year old with no past and no purpose, struggled to survive each day.Noah being a first-generation talent, with a common, unremarkable ability that never stood a chance against the Harbingers' overwhelming might, had spent years labeled a loser, while fighting to keep his head above water in a world that seemed to have forgotten him.But as fate would have it, everything changed one day when he was fighting for his life and at the verge of dying.[Congratulations, you have awakened an SSS RANKED Talent : Void Summoning][Congratulations you have unlocked one item : Eclipse blade!!][Congratulations : You have unlocked a new skill; Void Blink]He was reborn, and for the first time, he was no longer weak nor helpless.With all the creatures and the power of the void in his palms, he would bring an end to the apocalypse!

Cui Heng was transmigrated to another world and the system told him that the new world he was in was a high-grade Xianxia world.

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?