Unfathomable Senior - Chapter 45

Jeong Tae-ui, whose brother is the genius Jeong Jae-ui, is a former soldier who thinks he is ordinary. Jeong Tae-ui decided to work for half a year at the united nation human resources development organization ( UNHDRO) at the recommendation of his uncle Jeong Chang-in for half a year. Then got involved with a crazy man with pretty hands, Ilay Reigrow, and hand no idea. It starts rolling in a direction it wasn't supposed to.

Leo died like an idiot and got a second chance in a world that doesn't tolerate idiots. Dropped onto forbidden Oni territory, he's forced into a death hunt where survival should be impossible, but his body adapts through violence, pain, and sheer refusal to stay dead.One brutal victory earns him gold, status, and the attention of Iori, a warrior prodigy who's never tasted defeat. Now, traveling a continent where strength is law and gods play with mortals like pieces on a board.Leo faces a simple question: how strong can you become when dying just makes you harder to kill?

In the morgue full of Uchiha corpses, he opened his eyes…

A mysterious voice rang in my ear…

He looked confused: “Saving the ninja world, what’s the matter with me, the remnants of Uchiha?”

- Description from novelbuddy

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!