The God of Sky & Earth - Chapter 1099:

Fight. Heal. Survive.The Integration didn’t just change the Earthen Union—it tore it apart. Monsters, mayhem, and madness turned civilization into a battlefield.Yet, while the world crumbled under the weight of despair, David felt something unexpected: he felt at home.Even after being forced into the [Cleric] Class, David refused to yield. He adapted, turning his unwanted gifts into tools of both healing and destruction, forging himself into a battle-hardened healer unlike any before.

Over a million years ago, the first human contracted with the first Spirit. Ever since then, Spirit use has become commonplace. Humans used Spirits to carry items and start fires. Eventually, even start wars. Thousands upon thousands of years past and one day, one human did the impossible. He transcended his mortality and ascended to the realm above.

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.