Naruto: Did i Just Get Reincarnated as Gojo? - Chapter 33: The Ambitions of Poisonous Teaching Materials in the Ninja Academy

Untolerated by heaven, a boy was restricted by the most powerful spell.

He accidentally acquired a painting inhabited by nine souls that claimed to be immortal.

Then, the legend of a strong young man who violated heavenly principles against the course of nature began.

- Description from Novelupdates

The god king of Xiaoting in the upper realm fights down, and the spirit of the mixed dragon spirit is reincarnated on the earth, runs rampant in the city, and then fights in the sky.

Those who obey me prosper, those who oppose me perish!

- Description from novelbuddy

King Grey has unrivaled strength, wealth, and prestige in a world governed by martial ability. However, solitude lingers closely behind those with great power. Beneath the glamorous exterior of a powerful king lurks the shell of man, devoid of purpose and will. 

Reincarnated into a new world filled with magic and monsters, the king has a second chance to relive his life. Correcting the mistakes of his past will not be his only challenge, however. Underneath the peace and prosperity of the new world is an undercurrent threatening to destroy everything he has worked for, questioning his role and reason for being born again. 

A world from another dimension suddenly appeared in the Milky Way galaxy and collided with the earth. A spatial collapse occurred, which allowed the monsters crossing over from the other side to invade various countries, and the earth fell into great calamity.

The military was powerless against the invasion because modern weapons didn't work against monsters from another world. Under the desperate situation, a god-like figure appeared and bestowed blessings upon the humans to awaken their power. From then on, the earth regained its hope, and these extraordinary people were called Realizers.

Tenku Okuihara is a five-year-old boy who dreams of becoming a Realizer to protect the world and his family. But an incident changed his life goal from a hero to a grim reaper.