The Dragon is a draconic eldritch entity from the fictional universe of the Champions pencil-and-paper roleplaying game by Hero Games. It is the equivalent of a Great Old One from the Mythos in terms of effects and power level although it has a strong moral dimension which is alien (pun intended) to the Cosmicism of the original Lovecraft oeuvre.
The Dragon is the mystical manifestation of humanity's potential for evil. Which has existed within mankind's collective unconscious since the beginning of civilization, at least 6000 years ago. Remembered in its myths and legends as Tiamat, the Midgard Serpent, etc. The Dragon played a pivotal role in the rise of civilization among humans, inspiring men to discover and invent. Unfortunately it also brought forth the desire to oppress, brutalize, enslave, and slaughter. It taught them black magic, created vampires and werewolves, and taught them to use mystery and terror as tools to rule.
Ancient mages were able to bind its astral form with magical chains, and ever since the Dragon has been trying to escape and return to the physical world. To conquer mankind and establish a dominion in which man wold live with its boot on its neck, in complete misery. Currently on Earth there are several cults whom worship or serve the Dragon, the most powerful being the Cult of the Red Banner which is based in China. If aliens, gods, or the Kings of Edom were to threaten humanity with conquest, it would help them, for the pleasure of seeing mankind enslaved or annihilated.
It cannot be destroyed only contained, for the Dragon is a part of humanity. The Dragon's form is 400 miles long and nearly indestructible. A nuclear explosion would be the equivalent of a mosquito bite to the dragon. The "chain" binding it in the astral plane are the width of supertankers. If it were to be killed, mankind would be driven insane by the psychic backlash. The Dragon is nearly omniscient, possessing hypnotic eyes and a voice that you cannot ignore. Even though it's astral form is bound, he is still able to influence cults and sorcerers. Humanity continues to be corrupted by the dragon via its dreams and memories which the dragon can read and influence.
The Dragon sends fragments of its lifeforce into physical bodies which have been created by his human minions or in some cases himself. Which are formed out of ectoplasm or are golems that have been magically prepared. He uses these bodies to achieve specific goals or to spread his agenda. These bodies are magically limited in what they are able to do, having a tiny fraction of his power. One of these bodies is the "Death Dragon" which periodically challenges the martial arts champions of Earth in a mystical tournament, in which if it wins the Dragon returns to Earth.