Naruto: Escape From Konoha - Chapter 28: 27: The Second Coming of War

Jacob Steve, an Old Man, died at 116 after living a whole life.

But Jacob always had a dark side, which he always suppressed and hid from others.
However, in the later years of his life, when death was inevitable, he understood there wasn't any point in having wealth, knowledge, or desires if you couldn't have a life to enjoy them.

He became obsessed with fabled immortality and devoted his reaming life to extending his fleeting lifespan, but just like any other failed.

However, he mysteriously got another chance at life and found a way that led to fabled immortality.
But he was also forewarned that the way led to it was filled with blood and darkness!

In the end, Jacob chose it anyway with no way of going back, and it was also the start of his suffering and his icky, brutal journey toward the 'Immortality' he wanted so badly!

Xu Ke, the live-in son-in-law who had always been humiliated in the Lin Family, suffered countless indignities in this prestigious household.But who would have known that he was actually the heir of a top-tier wealthy family in the capital? When he inherits the family business, those who once scorned him can only look up to him.

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

A world where dragons serve as mayors, elves work in sales, and orcs brew coffee.In a city full of enhanced humans and wandering wizards, I became a young girl with psychic powers.“To do something so terrible to a child… These people are despicable.”“Human experimentation related to psychic powers is an international crime, punishable by at least the death penalty. This is absolutely unacceptable.”“Don’t worry anymore. From now on, you’ve got nothing to fear. We’ll take care of everything for you, little sister!”It seems the protagonists have misunderstood something.