Shinji Matou at Your Service - Chapter 894 - : Atrum and Medea

The formless ancient world was infested with despicable demons. They hunted and feasted on mankind, keeping the human civilization constantly in a weak and suppressed state.

During the first known year, a magical mountain descended into the world from the realm of the Gods. Carved on this enormous mountain was a message: ‘Heaven Prevails’…

After the Grand Descent, a name that was given to the descending of the mountain, the Three Great Sages made their ways to Mystic Mountain where they learned to harvest what we now call magic, establishing the Mystic Cults and eighty-one sacred shrines to help aid mankind with the cult’s mystic powers against the eternal fight to the death with demons.

- Description from Novelupdates

“Was trying to forget my past and live a peaceful life… a mistake?”His twentieth birthday was supposed to be a celebration, not his final moments—bleeding out on a bed, betrayed, and left to die.'Taking the life of a ‘good’ person makes you a murderer, but taking the life of a ‘bad’ one makes you a savior… Why?'As death embraced him, he whispered his final words—“The world’s kindness, right till the end..”…Only to wake up in an unfamiliar body.“Wait… I’m Noir Ravenlock?”A doomed heir, born to rule the world yet bound to a fate engraved with blood.In a world where morality shapes strength, survival demands more than just power—it demands understanding.And Noir, a man or perhaps a demon who once saw the world through twisted eyes, may just see something no one else can.

In the City of Crime, one law stands above them all: Only the strongest can live.

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!