Mercury

This planet which belonged to a different world, Mercury, possessed technology and political relations extremely similar to Earth. However, the area of Mercury was ten times that of Earth.

Thirty-six years ago, the planet was divided into several hundred countries and regions. Alas, a devastating calamity rained down upon Mercury back then.

A violent spatial storm swept the whole planet. When it finally subsided, the surface of Mercury was in total ruins. More than half of its buildings were destroyed, and nearly a third of its population was lost. It was a catastrophic disaster comparable to doomsday.

Just when the people thought that the troubles end there, mysterious spatial gateways suddenly appeared all over the globe. Countless species and quantity of Exotic Beasts swarmed out from these spatial gateways, attacking the humans' settlements.

These Beasts came in all sizes and shapes, possessing horrifying strength. Even the weakest among them were as strong as the most ferocious wild animals, while the strong ones couldn't even be killed with missiles, which only injured them severely. It proved difficult to eradicate them completely.

The war against these beasts lasted three whole years, and many weaker nations were completely wiped out by them. The strong nations suffered heavy casualties, too. As a result of the war, the human population was further reduced by half, leaving only a third of its original population alive.

The most unbelievable thing was that after these beasts died, they wouldn't leave a corpse behind. Instead, they would turn into balls of light and fly back into those mysterious spatial gateways, leaving Mercury's researchers unable to study their characteristics.

After three years of war, although the beasts were not thoroughly exterminated, they were driven out of the human settlements. From then on, both sides were evenly matched against each other.

While the war persisted on, the remaining countries on Mercury sought to cooperate with one another. In the end, the Mercury Alliance was established. They formed large amounts of expedition teams consisting of military and scientific personnel, and went beyond those spatial gateways despite the risks to their lives, looking for a way to thoroughly eliminate the beasts.

After the expedition teams entered the spatial gateways, they discovered that beyond the gate was an endless world. All their technological products lost their functions, and their firearms were nothing more than useless fire sticks. They could only rely on their cold weapons to fight against the beasts.

When the expedition team successfully killed off beasts in the unexplored world, they were surprised to find that while the beasts still don't leave a corpse behind, there was a certain probability of them turning into a mysterious card. Furthermore, those whose spiritual strengths were stronger than ordinary people were actually able to trigger a spiritual resonance with the card, thus activating the card and materializing it into a copy of the beast, a weapon, or a defensive armor, greatly increasing the expedition member's strength.

Such cards were collectively known as Beast Cards.

Those who were able to trigger spiritual resonance with the cards were known as Beastmasters.

From then on, humans ushered in a new age!

After discovering this secret, the alliance's coalition government immediately invested huge amounts of human resources to enter each spatial gateway. They killed the beasts in great amounts, and increased the numbers of beastmasters, one by one.

For the sake of bringing peace and stability back to Mercury, the first batch of Beastmasters switched their battlefields. They returned to Mercury to eliminate the Beasts, while simultaneously obtaining even more beast cards.

Even so, what surprised them further was that after the Beastmasters successfully killed off the Beasts remaining on Mercury, they found out that the beasts left behind corpses now, but never dropped any Beast Cards.

However, this much was enough for the alliance. With the corpses of the Exotic Beasts, related research could then be conducted. At the very least, the unique materials found on their corpses became some very advanced resources for them.

As the number and strength of Beastmasters increased, the scale of the war started tipping towards the humans's side. In the end, the remaining beasts on Mercury were nearly wiped out after a few years.

Just when most people thought that Mercury would finally be at peace, and the various government departments and research units, as well as wealthy corporations, were lamenting that there wouldn't be any more research materials, an endless horde of Beasts swarmed out from the spatial gateways once more, ten years after the first attack.

Although there wasn't much difference in the Beasts coming out from the spatial gateways from the first attack, the powerful ones among them could no longer be killed with missiles or other heavy weapons. In the end, they could only rely on the highly competent fighters among the first batch of Beastmasters to kill them after suffering heavy casualties.

It was only then that the Mercury Alliance realized the cruelty of the new age. A horde of Exotic Beasts would emerge from the spatial gateways every ten years, and the strengths of the beasts would be greater than the previous swarm.

To the Mercury Alliance, this was both an opportunity and a challenge.

The corpses of the varying species of Beasts would play an important role in elevating the level of technology on Mercury. On the other hand, with inherently stronger Beasts, that would also mean that Mercury was in danger of extinction if they ever slipped up.

Taking their living environment and the fact that heavy weapons weren't sufficient to kill the beasts into account, the high-tiered Beastmasters became the main force in withstanding the beasts' attacks.

With the passage of time, Beastmasters slowly became the most highly respected and aspired-to occupation. At the same time, their social status was also one of the highest.

However, not everyone was able to successfully become a Beastmaster. They had to be capable of triggering a spiritual resonance with beast cards, which required a certain level of spiritual strength.

After several decades, research had proven that in order to become a Beastmaster, one had to be at least sixteen years of age. However, if they were still unable to successfully become one by the age of eighteen, then their chances of becoming one would become abysmally low, with not even a one in a thousandth chance of doing so.