Divine Rune Awakening: Starting With Various Divine Runes and Dominating the World - Chapter 281 - : Gergon Descends!

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

No matter how twisted the world becomes, humans will always remain humans.In the face of their doom edging closer, their greed doubles instead of fading away. Their selfishness is unwavering—they simply want everything, even at the cost of endangering those closest to them.For that is the truth of humanity.So, if everything is linked to iniquities and sins, then unlike them, I won’t shy away from these possibilities—I will embrace them.---Synopsis:Kael, a young man from Earth—a dimension renowned for its technological advancements and brilliant minds—returns on a tour sponsored by his school.But fate has other plans.A Dimensional wave crashes into Earth, mutating the entire world into a grotesque landscape of unexplored horrors.Those who survived the dimensional impact awakened to newfound strengths, while those who didn’t perished—or worse—transformed into monstrosities far more fearsome than any beast.The world has returned to the law of the food chain. The strong will endure and rule, while the weak are devoured.Kael must cling to his sanity and navigate this nightmarish new world with a mission: to protect all he has left.But things take a darker turn when the system he acquired reveals an unexpected and horrifying backlash:{Consume human flesh}{Or perish within the next 24 hours}The clock is ticking, and Kael is left to grapple with an impossible choice that could seal his fate—or his humanity.

“Did you know? I was once the most powerful person in the world, undefeatable even by the gods. If only I can retrieve my body, I could resurrect once again.”“So what?”“So... who has hidden my corpse!”

In novels with a stud there is always a Senior Martial Brother like this:

In the early stages of the novel, his innate talent is high, his cultivation is good, his appearance is handsome, and he has an intelligent, cute younger Martial Sister as a fiancée.

In the middle stages of the novel, he is caught unprepared and defeated by a young disciple (the protagonist) in the sect who’s hardly remarkable at all. From then on, he falls from his godly altar and loses his brilliance. Even his young Martial Sister leaves him for someone else.

In the late stages of the novel, he continues to turn dark, going down the Demonic Path and becoming the major villainous boss. However, the protagonist still ruthlessly defeats him and his soul is eternally sealed.

Once Qin Mo opened his eyes, he discovered that he had become this Senior Martial Brother.

- Description from Novelupdates