I, Am a Living Yama, Empress Advises Me to Stay Calm - Chapter 151

Apocalypse befell, and roommates performed a skyward ritual.As the fog descended, the Book of Blood Spirit appeared in the hands of all survivors, and only those with a Contract monster could survive.Su Han directed his gaze to the neighbor who had already mutated and twisted, silently pulling out a gleaming fruit knife...Grotesque meat corpses, giant spiders with gaping mouths, eyeballs enveloping the city, one-eyed sharp-toothed hand monsters...Civilization fell, cities shattered, and all humans became meat for the monsters. There was only one way to survive:Use monsters to fight monsters.

A skilled but unfortunate modern-day assassin was killed in a freak accident. However, he soon found himself summoned to another world by an evil wizard, who had him possess the body of a boy as an experiment. After successfully planning the evil wizard’s downfall, he used the wizard’s body as a springboard to gain influence and power in his new world.

- Description from Novelupdates

Arriving in a strange world, Xavier realizes he's born into a family of hunters: Humans who hunt demons, cursed spirits, and various supernatural creatures.Xavier also comes to a realization that apart from espers- humans who awaken their attributes.They are Arcanists- humans who by going through the Arcane Ascension make use of the power of belief- Arcana, to manifest their wills onto the physical world.Not only that, but Transcenders- humans who consume divinity potions at the risk of losing their sanity also exist....And with the resurgence of the pathways.Xavier and his brother, Klaus are born into the Dark Era... an era also known as the Golden Age.Now both armed with a system each. The brothers must do everything in their prowess to put an end to the resurgence of the various evil gods and lunatics that endanger the lives of the normal citizens of the society.Churches of Gods, Prophets, evil gods, seers, oracles, and even angels of the lord can be both allies and enemies in this legendary tale that delves into the peak of mystery, fantasy, mysticism, and Lovecraftian horror!