MTL - Urban Tales of Demons and Spirits - Chapter 221 Destruction and Humanity

One day, a door to another dimension opened all over the world.

“Channel”

At the same time as the channel opens, different races appear on Earth, and mankind awakens its magical talent.

But…? Yoon Min-joon, was able to use magic long before the channel opened.

The forced escape of a reclusive loner who was once the only wizard on Earth.

“It’s dangerous outside the house.”

When you get to the other world, you acquire new properties, there is no limit for your achievements and you become an overlord…Welcome to my world…

- Description from Novelupdates

In the era of steam and mystery, becoming a correspondence student at the Thaumatology Academy was something Shad never thought of.

A whispering voice rang in my ears, who was reciting the poems of foreigners——

The old gods and aliens,

When the brassy rings of fate turn,

The golden runes are flickering.

steam surge,

the fire flickers,

Relic echoes,

The old gods revived.

The outstretched hand after the thick fog,

Pull back the hazy curtain of the crazy age.

Guests from afar explore the lands of the Old Continent,

Striking the melody of the next era.

Came here through the gate of time,

Shad put down his suitcase,

Look at the silvery moonlight overhead.

- 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.