Prologue:

At first they were just normal teenagers (not!) who went through every day life carefree and enjoyed life as much as they can. Then…that day came. That day, a deadly virus spread, infecting all those who crossed its path. It infected and the diseased fell to the eternal depths of hell. Because of this virus, they have sinned, and because of this virus, they found friends and possibly…love. This virus is bigger than anything mankind has seen before and in reality, the virus that infected these people is only a small part, a small evolution of the larger and deadlier form. Many have tried to fight against this virus, this abomination, but they have been defeated. The ones who fought to protect this virus were once just like them, sweet and innocent. Now, no matter who sweet or innocent they still are, they have become the slaves of the virus. The name of this virus? Koleenian Popuruitis. Its victims…the Ferocious, Assassins who are Naturally Sinned, and the enemies who have appeared to destroy this deadly virus, they call themselves after their goal to ‘Annihilate, Neutralization, Immunization, Throttle’.