Chronicles of the Heavenly Demon - Chapter 41: Exploiting The Enemy (2)

A teenager named Evan Mason was reincarnated into the magical world of Harry Potter and goes to school at Hogwarts!
With only his knowledge of the future and great talent for magic, he takes the path towards the top of the magic world, only to realize that ever step he took, changed everything!

- Description from Novelupdates

I, Zatiel, Abyssal Lord, Ruler of Death and Destruction, Nightmare of Dys, have AWOKEN!!!!!.

His life contains events that can shake the universe:
-Fighting against Tiamat, Creator of Evil Dragonkind, in the first circle of hell, while billions of demons and devils butcher each other beneath them
-Start a World War against the Heavenly Race, and transform himself into a Golden Sun while he slaughters their greatest warriors, the Archangel.
-Enter the Final Gate and fight against the Outer Gods.
-Tearing the nine levels of Baator during his battles against the Prince of Evil, Asmodeus.

With his memories as a ruler of the Abyss and a Universal Existence, Zatiel will rise again.

In the 21st century Earth gave Birth to greatest genius ever. A genius who Master myriad of arts. Medicine to Engineering. Mathematics to Micro Biology. Weapon Designing to Environmental control. Music to Painting. Dance to Martial arts. He mastered Everything.

When a person dies, they either die light as a feather (aka unimportant) or heavy as Mt. Tai (aka very important).