Death March kara Hajimaru Isekai Kyusoukyoku (WN) - Book 17 - 17-10. Purple Towers 2

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!

College was like a wake-up call for most people. Especially the likes of Christopher Owen, who spent the rest of his high school years messing around and pining for the boy he never had.Having had a frustrating high school year, he decided to dedicate himself to his studies in college.He flew many miles away from home, changed his looks, and hid his real identity from everyone. His plans were simple: study hard, pass well, no dating.But then he realized two things: life was anything but easy without the backing of his last name.And... he wasn't sure how long he could last before he jumped his roommate, who was obviously not gay.But lust wasn't love, right?Maybe he could indulge a little? Just a little, I promise.

A long time later, Ah Zhao and her younger generations started chatting about her own story.

“At first, I was selected by the system to become the man’s plug-in to help him reach the pinnacle of life.”

“-Then what happened afterward?”

Ah Zhao lit a cigarette and her expression had great changes:

“-Later, I became the wife of the Male God.”

- Description from novelupdates

The world was once at war with 10 alternate worlds. This was known as the Concept War and our world won 60 years ago. All of this was concealed so no normal people are aware of this fact in the current time.

After the death of his grandfather, the high-school student Sayama Mikoto is suddenly summoned by the giant corporation IAI. He learns this world is headed for destruction due to the acceleration of the Minus Concepts. To prevent this, negotiations must be undertaken with the survivors of the other parallel worlds so their 10 concepts can be released.

And so Sayama is caught up in the final battle to clean up after the Concept War which left behind so much enmity.