MTL - Azeroth Shadow Trail - Chapter 403 112. History of the Northrend Frontiers

A teenager who unexpectedly gets transported to the modern world from ‘the world of the immortals’ . He finds himself in the body of an ordinary guy. He wants to go back to his world and for that, he will have to practice to get stronger and investigate the reason why and how he crossed through to this world.

- Description from Novelupdates

He became a teacher at the best magic academy in the empire.
….For being mistaken for someone else.

The Immortal Dao is ethereal, and Immortals are hard to find.

Li Nianfan had descended into the cultivation world as a mortal. After learning that he has no hope in cultivation, he only wants to live a peaceful life.

However…

The dog he adopts becomes a demon king of a generation when it sees his poems and paintings. It manages to suppress an entire world.

The tree he plants behind his house becomes a World Tree after listening to his zither music, forming a bridge between heaven and earth.

He meets a passerby who is enlightened by him and becomes an immortal sage who leads an entire generation.

When he looks back—

It turns out that the scholar who had been pestering him for his calligraphy and paintings despite having crappy chess skills, is a chess saint from the Immortal Realm. The beautiful woman who comes to listen to his music every night is the number one saintess of the Immortal Realm…

A long time ago, the decayed main god space collapsed and disintegrated, and the wreckage was scattered in parallel universes, giving birth to a new space…

Countless ‘story worlds’ under control have also fallen into the void, regained freedom, runaway out of control, elevated to reality, and turned into reality.

At the same time, these “worlds” are polluted and corroded by the void, giving birth to greater fear and filth…

…

The space of birth feeds on the world.

They compete with each other, their tentacles penetrate through dimensions, invade different time and space, search for the legacy of the main god, drive the apostles to be minions, greedily tearing, seizing, devouring, and reclaiming one world after another, so that they can return to greatness.

…

The innocent eating melon and white waves with the legacy of the Lord God accidentally got involved in the parallel universe “Paradise of Fire” during a cross-border call.

After forcibly binding the demi-human blood, he became an excellent tool man who can repeatedly die, starting the legendary ‘dimension invasion career’.

- Description from novelbuddy