No Hero - Volume 8, The Beginning No. 1: The City of Sin

When he was categorised as an Omega at the age of 13, Rong Yi made a tiny little wish. In the future, he wanted to fall in love with a tall, handsome and elegant Alpha whom he could share a romantic love with, then build a blissful family with him and give birth to many cute babies together.

A few years later, he grew into a tall, handsome and elegant Omega and was passionately pursued by countless admirers of the same gender, while all Alphas backed away from him in face of his superiority.

This was not the life he wanted.

- Description from Novelupdates

Lee Se-Hoon, the blacksmith of humanity’s last desperate united force, fought against the demons until the very end. However, the result was mutual destruction, with the world coming to an end. The moment he took his own life over that futile conclusion—

“…What is this?”

He had regressed to his days as a candidate at the hero training institution, Babel Academy. Having obtained a second chance, he swore to use anything as material to gain victory this time. Anything at all!

The story is about a boy entering high school, who answers a strange call from a public phone one night. The caller challenges him to a bet: She’ll remove the birthmark which he sees as the cause of so many problems, and he’ll have fifty days to win the heart of a girl he’d considered far beyond his reach. And with this, a very strange summer begins.