CANON
The Ruling Dragon or Shouryuu (literally Dragon Lord) is an enigmatic entity or entities resembling a massive oriental dragon conferred uniquely upon the three destined rulers of the Three Kingdom period: Hakufu, Sousou and Ryuubi. It is proof of their birthright as conquerors. They confer massive power onto each of them, putting them well above A-rank regardless of their own skill, though each manifestation varies. Ouin managed to stop Hakufu's first manifestation fairly easily, however Koukin was only able to subdue it the second time with both a Hyakuhekitou and Ukitsu's help.
They do, however, create terrible destructive impulses that differ for each character. Hakufu's manifests a berserk, sadistic, psycho-sexual monster but less so than Ryuubi and Sousou. Sousou's is psychotic and the most malicious but otherwise completely in control, while Ryuubi's is completely out of control to the point of suicidal and self-mutilating. It is also the most evil, radiating deathly energy that consumes the life around it.
In addition to the three Ruling Dragons, other characters have been known to harbor dragons as well. Because of the qualities of Ryuubi's dragon, Kaku believed Toutaku may have possessed a dragon of his own. As a result of Ryuubi's dragon first awakening three years ago and the ensuing battle its presence caused, Ryomou possesses a dragon as well, however only Saji, Teifu, and the Deva of Seito, excluding Ryuubi, are aware of this fact. Koumei is believed to harbor a dragon as well, as Ryuubi witnessed it for a brief instant.
It has also been hinted several times that Chou'un also harbors a dragon, as whenever she opens her eyes, her pupils are cat-like and yellow in color, very similar to those of the awakened Toushi. Likewise, Kanu displayed identical pupils after Gakushin's aborted attempt to invade her mind, during her fight with Kyoshou's Three-Pillared Gods.
Typically when a dragon manifests, the eyes of the Toushi either glow red or turn yellow with cat-like slits. The forearms manifest bulging veins, which can sometimes extend over the entire body; fangs are also sometimes shown. Each dragon is of a different color; Hakufu's is blue, Sousou's is red, and Ryuubi's is gold. Unlike the manga, Ryomou's dragon appears to be her own and not Ryuubi's, and is black. Koumei is also shown with a silver dragon referred to as the Crouching Dragon.
Ikkitousen: Dragon Warriors
After the battle of Chi Bi
HakufuThe only original Dragon bearer to still have her dragon. However, she now has complete control over it and is able to tap into it's abilities and power easily.
Kan'uUpon defeated Sousou at the battle of Chi'bi, Kan'u absorbed the power of the Red Dragon. It is believed that she was meant to take on the Red Dragon all along. Though she has moderate control over her newly acquired dragon, she is still adjusting to its power.
Chou'unSubduing the full might of the yellow dragon in the battle of Chi'bi, Chou'un inadvertently took on the beast herself, releasing Ryuubi from her fate. It is believed the Dragon Jade had something to do with this, though Kan'u and Hakufu believe it was Chou'un's true fate from the beginning. The Yellow Dragon was controlled from the moment it entered Chou'un, further fuelling this speculation.
RyomouHousing the Black Dragon, Ryomou is easily as strong as the other three Dragon Warriors. However, Ryomou has to subdue her dragon's power with an eyepatch that she wears over her left eye, where the dragon has come to reside. Still struggling to full harness it, Ryomou is still afraid of her dragon and only uses it in the most dire of situations.
KoumeiThe Crouching Dragon, the Silver Dragon bestows great wisdom upon the child Koumei. It is because of this that Koumei is a valuable member of Seito. Koumei has more power over her dragon than any other, but this may in part be due to the fact that her dragon is less battle orientated.
???The orange dragon has yet to find it's host.
???The Green dragon has yet to find it's host.
???The Pink dragon has yet to find it's host.
???The White dragon has yet to find it's host.
???The Cyan dragon has yet to find it's host.
There are many other dragons out there... and they will be searching for their hosts.
(You cannot just decide to take a dragon. Dragon bearers are chosen by the Administrators and given over during RP. You will not be warned if a dragon is going to ask you to be its host. You will be given the choice in RP. Dragons only appear near the The Dragons of Haou (The Yellow, Red and Blue) so if you are in an RP with Hakufu, Chou'un and Kan'u (one or all), you have a good chance of being chosen later in the RP depending on what the Admin think =]