Naruto: Uchiha's Unserious Saga - Chapter 240: Roaring Youth vs. Mad Science

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

The hero who was killed by the demon king ended up reincarnated as the son of the one who killed him! Thus began the life of the hero who donned in the mask of the ideal demon prince to topple his own kingdom while doing his best to prevent anyone from discovering his identity―― But to do that and blend into the demon tribe society, he had to kill his former comrades. Nevertheless, to become stronger, to save humanity, he had to walk through all kinds of paths of carnage! This is the tale of the demon race’s fake prince destroying his own kingdom.

O Hero, Trample Those Who You Should Protect!

TN: Most part of the other character in the novel is depicted from a non-human perspective so expect something that is completely different from the common sense of human.

Daniella was ready to pull the trigger when she felt a warm hand touches her hand.

Davies had just been transmigrated… but he wasn’t happy about it.After all, it was now his fifth life, fourth transmigration, the third time he’s been betrayed and murdered, his second…(oh well… no more lines)Davies: Hey! Where are my second and first times…Author: I already said I have no more lines, so shut up and let me finish the synopsis!…After realizing that he wasn’t destined to be a hero and after many run-ins with the “Fated Protagonists”, Davies totally abhors those crybabies that have their heavenly daddies spoon-feeding them with opportunities to be strong, especially at the expense of himself as he always ended up with the short end of the stick in all his lives.Davies is now in his fifth life, and now has a system that seems to target protagonists. Even though he doesn’t understand why he's been used as a steppingstone for the “fated ones” in all of his lives, or why he keeps on transmigrating, or even why the system is just finally showing up after all the transmigrations he’s been true…According to the system, he was on his last life but at least now with the system at his side to aid him against the protagonists, he can wreak havoc and have his revenge against the protagonists in this world and also find out who is messing with his life… is how the story should have gone, but…“What the hell is with this busted system…!!!???”