The Black Book: Seven Deadly Sins - Chapter 127: Flashback

After being hit by a truck, the protagonist woke up in the hospital in the body of Ryoto, a step-sibling of Rito and Mikan Yuuki.

At first, everything seemed normal besides seeing anime characters in real life, but during class, he got a notification...

_________________

*PING*

*New quest*

Mission: Be the first to finish writing a test and do a Bully Maguire dance as you go through the hallway.

Reward: 100 SP, shop feature unlocked.

Fail: You'll be emo Peter for one week.

Calamity descends upon a a tranquil world in the black of night, transforming it into a death game! This a a true apocalypse, but this is not the end of humanity!

- Description from Novelupdates

Want to get super vision? Then let’s get some eagle blood.

Want to get super power? Blood of the Bear works great.

Are you going to surpass humans? Exactly, I have vampire blood here.

Do you want to be the ultimate creature? Very well, I have a drop of the blood of the ancient gods here.

…………

Become the headless mayor of the ancient, chaotic city of Arkham, where the gods breed.

Starting from blood therapy, Ross built an extraordinary shelter, a forbidden library, and a museum of the ancient gods.

Ross: We Arkham are full of talented people, and our folk customs are simple, hey! Don’t run! Haven’t visited Arkham Sanatorium yet!

Farming flow, invincible flow, behind-the-scenes black hand flow, Cthulhu.

- Description from novelbuddy

This is an alternate history. Decades after the fall of the Eastern Jin Dynasty, the world is still in chaos, although there is hope for reunification.