Ouroboros

Ouroboros (ウロボロス, Uroborosu) is a top-tiered dragon contracted under Yūmei Kokūzō, and serves to be one of his most powerful summons.

Appearance
Ouroboros serves to be one of the largest dragons in existence. He much unlike other dragons though, appears to be nothing more than a corpse; his two pairs of wings appear tattered, and his abnormally-sized skeletal structure is physically visible for all to see. He has a pair of crudely-rounded horns. Uniquely, he has a total of nine tongues, each of which resemble dragon-headed serpents, and are used to exert a variety of poisons.

Personality
Ouroboros is a grim creature with very little respect for the living. While not deceased himself, he holds those that are in high acclaim, he himself envisioning a realm where all would reside in a state of undeath, although truly seeks nothing more than to rule over the underworld itself, one that he himself had birthed. After Ouroboros met Yūmei, his respect for the living increased to the point where he allowed the forging of a pact between the two, somewhat hoping that he'd be able to terrorize the realm of humans for a minute or two per year.

Abilities
Ouroboros is a profound user of poison, of which he generates from the depths of its maw to produce a variety of effects, of which are exerted from his nine tongues. Such effects can include upon inhalation, physical paralysis, impairment of all five senses, captivation in a genjutsu, and even death. The fact that none of these will affect him makes it an absolute necessity to fight him where the mist (that he generates) cannot completely enshroud the environment. He is able to consume all forms of poison, and rapidly convert them into raw chakra; the antibodies he possesses are near-infinite, even the most potent of poisons would not function fast enough for him to develop an effective immunity against it. As a top-tiered dragon, Ouroboros possesses a cataclysmic reservoir of chakra.

Influence
The Ouroboros often represents self-reflexivity or cyclicality, especially in the sense of something constantly re-creating itself, the eternal return, and other things perceived as cycles that begin anew as soon as they end (compare with phoenix). It can also represent the idea of primordial unity related to something existing in or persisting from the beginning with such force or qualities it cannot be extinguished. The Ouroboros has been important in religious and mythological symbolism, but has also been frequently used in alchemical illustrations, where it symbolizes the circular nature of the alchemist's opus. It is also often associated with Gnosticism, and Hermeticism. Carl Jung interpreted the Ouroboros as having an archetypal significance to the human psyche. The Jungian psychologist Erich Neumann writes of it as a representation of the pre-ego "dawn state", depicting the undifferentiated infancy experience of both mankind and the individual child.