Mr. Yuan’s Dilemma: Can’t Help Falling in Love with You - Chapter 281 - Don’t Be Afraid, Baby. I’m Giving You a Whole New Experience

Until he became the lowest-ranked master, his lonely and luckless life never changed.Suddenly one day, a descendant injected him with a nanomachine, and the machine started ‘speaking’ to him.[I am the seventh generation Nanomachine manufactured by Sky Cooperation, and I am operating as a central nerve connected to your brain.]“What? What are you talking about?”This was beyond the boy’s knowledge, he turned pale.The Nanomachine linked to his cerebrum realized the User was not understanding a single word it said.“Who are you, and why are you doing this to me?”[“I am the seventh generation Nanomachine.]“Nano Machine?”[Yes, Nanomachine.]The boy’s face hardened.Mashin was the deity the Mashin Religion worshipped, along with the Sacred Fire.The religions’ Master communicated with Mashin.“Um, are you really Mashin?”The boy knelt down and asked with a trembling voice. At this, the Nanomachine attached to his cerebrum realized it had been misunderstood.

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?

As the other person’s stand-in, he humbly falls in love with the president.

Xue Yingshuang was a stand-in, and humbly fell in love with Xing Yun…’s salary pay.

As the other person’s stand-in, Xue Yingshuang wishes he could never be separated from the president for the rest of his life.

He is a stand-in, and he must get off work at one o’clock.

The president’s white moonlight came back, other stand-ins were sad, and depressed. They couldn’t handle the jealousy and finally left with a dead heart.

Xing Yun’s white moonlight came back, and Xue Yingshuang had no waves. He enthusiastically served white moonlight and shone brightly at work.

Xing Yun: Little stand-in, is this your little trick to seduce me?

Xue Yingshuang: Misunderstood.

Xing Yun: Do you want to suffer in silence and finally leave secretly, driving me crazy?

Xue Yingshuang: You think too much, how can I leave? I still have half a year of social security before I can receive unemployment insurance.

Xing Yun: ?

Xue Yingshuang: I also haven’t received the year-end bonus you sent me yet.

Xing Yun: ??

Xue Yingshuang: I didn’t get my paid annual leave either.

Xing Yun: ???

Xue Yingshuang: Wait until I get the money and put it towards a vacation.

- Description from Novelupdates

At 79, Adom is an old mage who has known nothing but illness and regret. When the world finally burns and all hope turns to ash, at the last beat of his fading heart, a mysterious being appears in the dimming light with a simple question:“If you could try again, would you?”What's left to lose when you've already lost everything?A handshake seals the deal, and Adom wakes up on his old school grounds, sixty-seven years in the past. When everything is still possible. A second chance with all his knowledge intact, his memories preserved, and his youth restored.This time, Adom wants it all: to feast on food he's never had, to travel a world still full of wonder, to finally live the life he dreamed of. There's just, as always, one small catch—he needs to prevent the end of the world first.But as Adom will soon discover, changing history might demand sacrifices even greater than watching it burn...