MTL - I Truly Am The God of Learning - Chapter 735 Lifeline

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?

After an ominous prophesy is discovered, the swordsmen of the kingdom of Ensis must band together to avoid the fate that has already been foretold.

An underprivileged prodigy, a cruel, ruthless world, and an epic story of battle and conquest. A young man with an exceptional inheritance leaves the small, rural city from which he hails on a journey to find the girl of his dreams. He defeats countless prodigies, sweeps through all forces that dare to stand in his way, and progresses step by step toward the pinnacle of all the worlds!
“I’m not targeting any gods in particular. All I’m trying to say is that all gods are trash in my eyes!”

- Description from Novelupdates

The second prince has come of age. To celebrate the advent of such an occasion, the search for a suitable bride began. My younger sister was expected to go to the Royal Palace as a candidate. However, despite this, she eloped the day before her departure. I, the older sister she left behind, looked almost exactly like her – so much that we were often mistaken for twins…

One month, right? For just one month, shall I substitute in for my sister?