Why Did You Summon Me? - Chapter 588 - The Battle For Control

The protagonist, Punk, is a cautious, cold-blooded, and ruthless Mage.

His goal is always his top priority, over feelings or morality. When unnecessary, he doesn’t like to act like pigs to eat tigers; there are almost no life and death struggles, sometimes risky but steady progress. No strong enemy everywhere, Instead, Punk is always a strong enemy of others.

And he has a very keen interest in the secrets and teachings of the Netheril civilization.

A mecha otaku is reincarnated into another world as Ernesti Echevalier (Eru). In this world there exist huge humanoid weapons known as Silhouette Knight. Dreaming of piloting those robots, Eru, with childhood friends, Archid Walter and Adeltrud Walter: together they will aim to become a Knight Runner, pilot of Silhoutte Knight.

They love gold, and they love silver. Even more so, they love gems that dazzle, like stars across the skies.
Firearms, jewelleries, and precious metals; A collector’s world will not be complete without antiques.
Storage auctions, old goods trade, re-estate sales and gold-digging. But the truth is, if one wants to make money, then the supreme way is through searching for the legendary treasures.
Holding the fort, there’s an ocelot, a wolf, and an Andes condor. At the side, there’s a loyal hound, an irascible ape, and an African honey badger. Who said that you can only rely on humans when treasure hunting?!

- Description from Novelupdates

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!