Alright so I'm thinking something like Kaze no Stigma, but with a slightly different concept. If you have not seen the anime that is fine, the concept is not hard to grasp. Now that that is out of the way I'll begin to regal you all.
When the world was still young and human beings still a fledgling race, the spirits began to make contact with them bestowing the powers of the elements. For it did not take them long to realize that these semi-intelligent humanoids would conquer the planet, although the Thropes were a pleasing second choice they sought to to rule everything violently with blazing emotions. In their intellect the spirits devined that at least humans were capable of compassion more easily, but they had been ignorant of what the leader species would do with raw undistilled power. Which was wage war and wreck havok on the beings and lands around them, and to crush their opponents underneath their feet.
This lead to the harsh decline of the beast kingdom more commonly refered to as thropes, or beings between beings that neither belonged to beasts or man. They still exist in the shadows largely biding their time, many no longer hold grudges, although the ones that do have made themselves immortal and evil in nature. The spirits all but waned away making the humans weaker, but no less dangerous. As they had made constructs to harness the power of the elements, some humans are still able to weild these powers. Many beleive that tales of this are of pure fantasy, others seek to control these powers themselves enslaving the spirits that have brought life to the planet.
Others bear the stigma of contractors, the original spirits of old, to aide them against the coming darkness that seems to pollute the lesser spirits ravishing the Earth. Some of you are new contractors, some of you mearly weild the power of the energy of spirits around you, yet still others of you are Thropes be it lycan, dragoon, tigris, or one of the many other types hidden by the reality constuct that forces normal humans to forget the supernatural deeds performed around them. In either the concrete jungle or the tropical forests you begin finding yourself consistently drawn to a human town on the eastern coast of the United States of America.