Before Bahamut was crowned, dragons were fearsome, vicious creatures. When one was hungry, you pray that you or your village weren't on the menu. They spewed fire, ice, or demon's breath recklessly, creating forest fires, frozen tundras, or miles of decay without a care towards their actions. With the birth of the King of Dragons, they tamed considerably, shockingly so. Don't get them wrong. Dragons were still very dangerous when provoked into anger, but no longer did they cause mindless havok across the world. And with Bahamut on his throne, the Dragon Riders were established.
Dragon Riders are speculated to have originated before written history, or so the Draconians claimed. It was also known that any sentient being from humans to fae to anthros could be a Dragon Rider, but there were conditions to be met.
Between the 'Riders and their partners were very special, one-of-a-kind bonds. More times then not, the 'Riders cannot feel
Dragon Riders prided themselves for a reason: what other kind of chosen people (short of the Draconians) could tames such magnificent creatures that rode the skies, free from restraint, and as royal as any king.
Dragons were to be respected, even the ones of the Dragon Riders. However, that didn't mean they have to respect each other...
It was common knowledge that there were five all-mighty teams, the ones that could shred you to pieces with their partners if looked at the wrong way.
There was Chang Wu Fei, Prince of the Draconians, and his speaking Jade Dragon, Nataku. He traveled with Hiei and Kuro, a Fire Demon and a Black-snake Dragon respectively. Both were not to be underestimated, despite their stature and stoic faces.
Drake Yuuji was one of the many humans among the ranks, but the third to reach the top five with his Copper Dragon, Nite. Nite was silly in appearance, as it seemed docile and stupid, but once it start attacking, the miniture dragon could rival Bahamut himself.
And finally, there were Seto Kaiba and Katsuya Jounouchi. Both were card-mage humans, both were strong and competative... and both loathed each other with a passion. Which was a sad ordeal indeed, as they possessed two of the seven rarest dragons in the known world: the Blue-Eyes White Dragon and the Red-Eyes Black Dragon.
The councilmen of the Dragon Riders have often urged these two to put aside their differences for the sake of their partners' survival. But to try and cut the hate between them with the strongest sword would snap the blade in half; it seemed hopeless.
The Blue Eyes and Red Eyes were thought to have been extinct, and yet, both of them waltz in there almost simultaneously, Jounouchi two days before Kaiba.