It didn't happen overnight, the apocalypse began after seven days of weird events on a global scale, and then everything changed. Hell descended on the world.

Animals mutated into monsters that could be as tall as skyscrapers, trees gained humanoid form and a taste for human flesh, alien races similar to the fruits of the imagination of humans came through portals, demons, winged angels, elves, beast kin, tauren, slimes, zombies…

Unique pocket dimensions containing other worlds called 'secret realms' appeared home to many treasures, ancient ruins, alien races, and great mysteries.

Humanity's savior also descended, Cards. The power to summon beings to fight for you, control thunder and lightning, cause tsunamis, transform into alien races…the power of cards encompasses all.

Grey Ash Grade summon [Malevolent Hound] chasing you to the ends of the earth,

Red Steel Grade summon [Flame Titan] its mere presence causes all to cower in fear in the searing heat,

Black Iron Grade Consumable [Smelly Shit Lotion] in stinkiness and filth your life is as tough as a stone in a latrine,

White Silver Grade Spell [Rain of Giant Spears] In a moment hail like the judgment of god rains down upon you with each fragment in the form of a spear as large as a tree.

But like a wicked joke that reaped the lives of billions, this apocalypse despite being so game-like was to be cursed as the worst game to ever exist: there was no system, no introduction, no guide. Humans were flung into this new world and still had to blindly grope in order to understand the rules and gain the power to survive.

Even 15 years after the apocalypse, the former rulers of the earth remained overthrown with no sign of regaining their former glory.

History was changing and the dark era of humanity had come, hundreds and thousands of years later perhaps due to a series of events the 'Blood Era of Extinction, 'Dawn of the Magic Cards', or 'Era of Gods and Demons' would end with sacrifices of many martyrs, and humanity could once again stand proudly amongst the myriad of races.

However...

The course of history was forever changed, when a certain item crisscrossed the fates of a pair of woman and man, sending them back before everything started.

Thus began the era that would be dubbed 'War of Gods, Demons and ...Kings'.

*There are two protagonists, one female, and one male.