I occurred to me, that my description in the opening post feels a bit lacking, and because I ended up writing out the entire summary, I'll just post it here.
Long ago, the world was in a Golden Age. Advances in science saved the lives of millions, studies run by the many institutes of magic discovered hundreds of new uses for their power, and for the first time in thousands of years, the cultivators sects were united through the brotherhood of a generation of heaven-defying geniuses.
However, an unknown scourge soon brought the world to its knees. Monstrous beasts ravaged the Land, coming from the black rifts that appeared throughout the 10 nations. With guns, magic, and the might of the cultivators from the many sects, the world fought the monsters, but soon understood they were doomed from the start.
As they stood against impossible odds, the peoples of the world made a great sacrifice. 100 individuals, chosen for their strength and knowledge, were to abandon their homes and their time, to wait for the future, when perhaps thing would be different.
And now, 2000 years later, many of these figures have begun to awaken, to a world far weaker, yet far strong as well.