Academy’s Undercover Professor - Chapter 209

The Immortal Path led to Longevity and Sovereign was heading in ease. When the Longevity was no longer in ease, all living beings were just prisoners. Conspiracy, internal strife, and the invasion of the others, all of it emerged together. 

In such a world, there was such a young man. He made his way upstream, stepping on blood, defying the emperor, destroying the various kings, and slaughtering his way through the hundred clans to form an Immortal Path towards the throne of Sovereign! The Immortal Path was endless, while the Sovereign was limited. He used his blood to forge his immortal legend.

- Description from Novelupdates

I lived my whole life as a s*ave, bound by a leash. But there was one thing that I was able to choose for myself: the place where I would die.“…Any last words?”My only friend asked me in a calm voice, and I quietly replied as I closed my eyes.“Waaaah!”…Waaaah?To cut to the chase, I was reincarnated. And not just as anyone, but as my friend’s youngest grandson. So, what am I going to do now? Well, what else can I do?“I’m going to cause chaos.”

"When will people understand.... I'm only half insane?"

As a promise, he went out into the world as an assassin. 3 years later, after becoming the Supreme Assassin, he gave up on everything he had and returned to the ranks of ordinary people. But one day, Kismet, a mystical game created by the National Research and Development had appeared.

Enigmatic hands, spectral frame, and one cunning strike just like the swing of the Grim Reaper. The Supreme Assassin takes on the mystical world, and how his legendary tales sets off, progressively ascending the altar to becoming the best.

- Description from Novelupdates