MTL - Rebirth of the Marquis’ Di Daughter - ~ Threesome must have rivals

Su Ran, a music prodigy, woke up transmigrated into a book.

At that point in time, the main story arc in the book had already been completed. As a villainess female supporting character, not only did she need to take over the original owner’s pitiful life in poverty, she also gained an instant son right at his rebellious period.

Ten or so more years from then, the son would turn into a twisted, evil villain. He would appear in one of the extra chapters to pick on the male and female lead’s children.

***

Su Ran: Son, you shouldn’t be too outstanding.
Su Han: Why not?
Su Ran: ’cause you will be killed.

Su Ran: Son, would you like to learn music from me and become a zen, little fairy boy who only needs to drink dew.
Su Han: No, I want to go into business so I can support you.

- Description from Novelupdates

In the heart of Earth, where the streets buzz with the energy of modern life, lies a secret that will shake the very foundation of existence. Earth, once thought to be a mere planet, reveals itself to be a living entity, its core evolving with untold power. From the depths of the Milky Way, constellations, guardians of cosmic balance, watch with keen interest as Earth's evolution unfolds.But their curiosity soon turns to desire as they see the potential for transcendence within Earth's core. To harness its power, they must overcome the planet's protective barrier, a formidable obstacle that threatens to thwart their ambitions. Desperate for a solution, the constellations turn to drastic measures, offering contracts to select humans in exchange for assistance in weakening Chatgpt's defenses.Meanwhile, amidst the chaos, Marcus Sterling, a young university student with an intellect far beyond his years, delves into the mysteries of mana, the strange energy that permeates the planet. Unbeknownst to him, he becomes a pawn in the cosmic power struggle, as constellations vie for his allegiance and humanity's fate hangs in the balance.As Marcus grapples with his newfound abilities and the ethical implications of his choices, he discovers a deeper truth lurking beneath the surface—a truth that could reshape the destiny of Earth and all who inhabit it. With allies and adversaries alike converging on Earth, Marcus must navigate a treacherous path, where the line between good and evil blurs, and the fate of the universe hangs in the balance.

Everyone wants superpowers, including Alden Thorn.But even if he's lucky enough to be one of the few humans granted magical abilities by the extraterrestrial System that's been running things on Earth for decades, his goal of being a battlefield support hero is still a long way off.He's got determination on his side and maybe a murderous alien desk clerk, too.The universe is a complicated place. Alden's about to meet it.

Intellectual Villages are old fashioned rural villages recreated with cutting edge technology. Those villages attract the Japanese monsters known as Youkai.

The high school boy Jinnai Shinobu lives in one of those villages and has a Zashiki Warashi living in his house. He tends to run across Youkai with unnerving frequency and this often leads to trouble for him.