The Tsunami that hit Japan in the Year 2012 destroyed the Nuclear Power Plant causing radioactive substances to spread like wild fire throughout the country. The radioactivity level was rather higher in the Northern region of Japan compared to the rest. Not long after, the government took actions to evacuate the citizens from the North. The radioactivity level was so high in that area, it started acting in the form of a virus. Anyone infected by it could contaminate everything and anything they touches. After the medical centers found out about this strange phenomenon, the government then issued a policy that every infected person would be sent back to the North Of Japan , isolated from the rest of the country to prevent more deaths and infections. Due to this act, the infected hosts were exposed to more radiation causing abnormal physical growths. Some grew ears that are as long as elves while some resembled hybrids. These group of people were left with no shelter , food nor any basic needs. They became wild animals in the ruins of North Japan. After 10 years of isolation, the food sources had ran out and the infected were pleading for food. But there was no form of communication that they could use to signal help. The adults gave up all their food for the younger ones.It was Hell as young watches the old passed away one by one. But what the infected doesn't know is that the rest of the world that had been secretly surveying the North Japan all this while , watching the infected slowly starves to death. After a year or so, an international announcement was made that the North Japan was finally ready for humans to live again as the radioactivity level was back to normal and the infected had been extinct. The UN helped investing in Japan to rebuild the North. People started migrating back to the North and everything was back to how it was except that the North had been constantly reported of murders occurring around the city. At every crime scene, the was a poker card present. Slowly, people created conclusions that the murders were facilitated by the same group , nicknamed as the Cards.
(Excuse my noobish english)
So basically, whoever that is interested would join as a member of the Cards. The Cards is actually a group of mutated murderers who had secretly survived(the world still have no idea about that they were mutated). Their aim is to take revenge on the government that caused their pain (The Isolation). The Cards is a group full of people who are mutated so you could choose to be a mutant with angel wings, elf ears, hybrid etc. The leader of the card goes by the name Joker. But Joker went missing a few years after the Cards become active. Her location is still unknown. (She will be introduced as an NPC-like ). So yep...