Akuyaku Reijou ni Nanka Narimasen. Watashi wa『Futsuu』no Koushaku Reijou desu! - Chapter 10: Spirits, celebration, and immature adults.

“Jiang Yu transmigrates into a novel and becomes a side character in the book.

A Di [legitimate-born] daughter of a noble house turns into an abandoned daughter. No father to dote on her, no mother to love her, no problem. She uses one silver needle to save a dying man. What’s so unusual about a medical injection? She roams all over the world with a scalpel in her hand. Cutting throats, cutting open abdomens, cutting open skulls to mend bones. With amazing medical skills and ethics, she gathers a flock of officials, obtains the will of heavens, gains public favor, and receives Taizi’s [Crown Prince] doting. In the midst of a powerful momentum, her cheap father comes to reunite. She coldly refuses to go home or acknowledge ancestors.

“I was abandoned by you over and over again. Now you want to use familial affection to coax me back. You don’t want to recognize this daughter. My heart is cold, I want to leave. Beat it, father!”

- Description from Novelupdates

Humanity was living peacefully on Earth for millions and millions of years until the day unknown monsters from beyond space invaded them.

When humans were about to disappear, some people with abilities came out to the light and shared their knowledge and powers with the world, and together, they managed to push back the invaders during a terrible war that had lasted for years.

This war had created many orphans, and among them, Kye had lost everything, even his parents. And the only thing he received from their death was a pale-looking necklace.

However, once the necklace finally activated, a system was given to him, and his life changed completely.

The system gave him quests to do, and Kye complied. He was getting stronger every time he achieved them, until the day it gave him a weird quest.

[You have one day to kill the one who had sinned. If you do not kill, you will die.]

When he woke up, Lin You found that the world had changed drastically.

Monsters of all races roar and bombard wildly, field magic cards form a deep sea out of thin air, royal tombs, skyscrapers, and trap cards are infinitely possible.

Duellist colleges and universities all over the country are rising, and the miracle secret realm is full of dangers.

This is a world where all people chase cards, and the era of card duelists shines.

- Description from novelbuddy