Re:Zero Kara Hajimeru Isekai Seikatsu - Chapter 78Arc 7, - “A Volatile Reunion”

Venshiro, a young ronin bound to the Black Vein Blade, is hunted by clans who would kill for the curse he carries. Every time he draws the sword, it takes something from him—his memories, his soul. But the blade remembers everything.And now, it wants more.

25 years ago, Gu Yuan who had a terminal disease was found to possess one kind of kind rare powerful gene.
In order to allow the gene to pass through the generation, she donated out 5 ova before the failure of her surgery.

25 years later, today she awakens. Her 5 ova had now turned into outstandings and famous men.
Mmmm….who is it that laughs at her for being old-fashion, backward, have nothing at all and penniless?

The world-renowned tycoon prince accompanied Gu Yuan for supper. The media was in an uproar, is the prince going to be in love?
Tycoon Prince: That’s my mother.

The media tycoon who controls the world public opinion, stake a thousand pieces of gold on one throw for Gu Yuan. The whole audience was in an uproar, an unknown girl going to marry into the noble family?
Media Tycoon: That’s my mother.

The film emperor with thousands of fans who received worldwide attention broke his 8 years practice and for the 1st time ever unexpectedly composed music for Gu Yuan. The whole internet was in an uproar, is this film emperor’s love of the century?
Film Emperor: That’s my mother.

17 years old beautiful young boy genius with IQ that beyond compares named the asteroid he found after Gu Yuan. The world was in an uproar, is this love between an older woman and a young boy?
Genius Boy: That’s my mother.
……
All the supporting males and females who had ridiculed and bullies Gu Yuan before cried: She actually has how many good sons?!

Finally, when the handsome world most eligible top billionaire accompanying Gu Yuan for shopping, the crowds immediately shout loudly: She must be his mother! His mother! His mother!
The aloof top billionaire: She is the mother of my sons.

- Description from Novelupdates

“Li Qingshan, as the eldest disciple of the Ascension Sect, the prince of the Dayan Dynasty, was actually bewildered and let go of the Demon Sect Heavenly Concubine, do you know the guilt?”

“I would like to give up my status as a big disciple, be imprisoned in Siguoya, and wipe the forest of steles.”

“Yes, but you must abolish your cultivation base, smash your roots, and you must not go out for the rest of your life!”

Since then, Li Qingshan has been living in seclusion, thinking about crossing the cliff, wiping the forest of monuments, and actually activated his full-level comprehension.

[You watch carefully, stimulate your full-level comprehension, and realize the Dahe sword qi]

[You watch carefully, stimulate full-level comprehension, and comprehend triple sword strike]

[You watch carefully, stimulate full-level comprehension, and comprehend Fantian Yin]

Eighty years later, the Immortal Dao Golden List came, ranking the masters in the world, and Li Qingshan directly occupied the first place.

The list’s evaluation of him – the god of the world!

- Description from novelbuddy

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.