Quetzalcoatl is sometimes called the Feathered Serpent, the Good Serpent or the Winged Serpent. His brother, Catylketz, used to rule the light dragons alongside him and they were both just and powerful rulers.
Then Catylketz became corrupted by darkness. Once a light dragon himself, he transformed into a powerful and malevolent darkness dragon with a thirst for world domination. He rose up against Quetzalcoatl and tried to attack him but the dragon god defeated him. Later, he tried again with an army of dark dragons, including the terrible chaos dragons. Outnumbered, Quetzalcoatl called upon his light dragons, who rose up to defeat the dark army. Catylketz was apparently killed but he may still be out there somewhere.
Quetzalcoatl is a large, legless serpent with feathers instead of scales and enormous feathered wings. He is of Draco quetzalcoatylidae and is often portrayed as multi-colored, as was the tradition of the South American tribes who worshipped him.
The Aztecs worshipped Quetzalcoatl and made sacrifices to him often, believing him to be infinitely powerful. Quetzalcoatl disapproved of the sacrificial practice but could not reveal himself to the Aztecs due to the final spell cast by Catylketz, just before being overpowered, to hide him from his allies and reveal him to his enemies. This also had the unfortunate effect that he could not show himself to the light dragons anymore, but they still believe in him, even to this day.