Tenebroum - Chapter 30: Tainted Waters

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?

June 15 of the year 2010, the third awakening happened. Several smaller worlds had returned to connect with the main world as living beings of different races started to appear and some people managed to connect with the origin and gain control of various powers: control of fire, of water, of wind, of air, and of earth... In the midst of all these confusions, towers that gave unimaginable powers began to appear in all corners of the world, where those who already had powers could upgrade and become more powerful or even those who did not have powers could receive powers through tests of the tower. And because of these towers, conflicts started to happen in all corners of the world by those wanting to monopolize these towers.

Luan Dimas was betrayed by one of the people he trusted most. However, in his final moments before being killed, he was transported back to four months before the third awakening that started the apocalypse on earth. Being a man who lived for a thousand years and had accumulated several techniques, he now had a new chance to correct some of his early mistakes. Luan decided to make the most of this new chance that the heavens had given to him.

A novel revolving around being transported to another world with an op system. The mc spends his day chasing skirts and doing missions to level up. A standard journey to the top with lots of girls from various animes and games with a twist of that gaming feel (hunting mobs, doing missions).

- Description from novelupdates

This story is about a rookie researcher, who was forcefully dragged away from his restful life, compelled into facing various killers and zombies, always having to risk his life at the brink of death, and finally becoming an advanced researcher that is acclaimed by all. And throughout his adventure, he met an alluring(?) killing machine, who he started to have fantasies on after they had an accidental kiss…

Xiao Yan: Did I fall for him? But he’s a man!

Maya: Who knows…. maybe it’s the other way round?

- Description from Novelupdates