MTL - Library of Heaven’s Path - ~ Fan Wai II, Luo Qiqi Xiaozhuan, big marriage!

In the era of steam and mystery, becoming a correspondence student at the Thaumatology Academy was something Shad never thought of.

A whispering voice rang in my ears, who was reciting the poems of foreigners——

The old gods and aliens,

When the brassy rings of fate turn,

The golden runes are flickering.

steam surge,

the fire flickers,

Relic echoes,

The old gods revived.

The outstretched hand after the thick fog,

Pull back the hazy curtain of the crazy age.

Guests from afar explore the lands of the Old Continent,

Striking the melody of the next era.

Came here through the gate of time,

Shad put down his suitcase,

Look at the silvery moonlight overhead.

- Description from novelbuddy

Perhaps it is the choice of fate. As a senior otaku, Qian Lingfeng got the “steel shell system”. However, when he swept the world with the system, became a local rich man, made all kinds of beautiful women, opened a harem, and realized the ultimate fantasy of thousands of otaku, he found that things seemed far from simple!
When the end comes, biochemical zombies suddenly come down, fierce beasts are in power, bloodthirsty zerg roam to kill the world, and human lives are comparable to dirt. Where will weak human beings go in this world? Is humanity going to be extinct? Or … can an otaku save the fate of the human race?

- Description from Novelupdates

Lu Ze transmigrated to the interstellar era two thousand years later.
The previous owner of this body had lovey-dovey parents and a cute little sister. Although his cultivation talent was ordinary, his life was fulfilling. It could be said to be a dream start. Lu Ze was very happy.
However, as soon as he slept, he came to a strange dimension.
He almost got taken out trying to fight an one meter tall huge white rabbit. After making the arduous kill, Lu Ze found that things didn’t seem to be so simple.
After killing prey in this dimension, he could get little orbs that could be used for cultivation.
This was going to make him an eternal jungler.
But he seemed to be able to hope for domination of the cosmos and invincibility?

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.