Death Guns in the Higher World - Chapter 16: Toward the Adventurer’s guild

agreed. He thought they might just talk, have a few drinks, and that nothing significant would happen. However, she invited him to a hotel, and they spent the night together.The next morning, she told him it was just a one-night stand and that they would probably never meet again. She said goodbye and left. Ronan also decided to treat it like that.The next day, at his college's hosting club, Ronan was given the responsibility of hosting that year's annual function, where they had invited a singer.When Ronan looked up at the singer, he was shocked—it was the same woman he had spent the night with. After checking her history and social media, he formed an impression of her. Every picture she posted was in revealing clothes, bikinis, or almost nude outfits.He concluded that she was just a promiscuous woman, likely driven by lust, and that she had probably chosen to spend the night with him simply because she found him handsome.Understanding this, Ronan decided to focus on his work. That morning, she had made it clear that it was just a one-night stand and nothing more. He would treat it exactly that way and carry out his responsibilities.Protagonist has System---No NTRIt's Harem, with many girls but The Singer is Main Heroine.

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?

Lin Xuan was transmigrated to a fantasy world and had a one-night stand with the powerful Ice Empress.