In the beginning, way back during the much earlier days of Ancient China, long before even the great Grandmaster Dashi was ever first conceived, there was once an evil and dangerous force of darkness that was just so powerful and so vile that even the very spirits of the land feared him. His name was Lord Serpentius, the original villain and grandmaster of the Heylin side, and his only real major goals in life were to see his evil influence spread throughout the land and to have all of existence bow down in his wake. Now, he, of course, wasted no time in spreading his dark magic to wherever he went in ancient China. Why, as a matter of fact, it was actually through this very same dark magic of his that such evils like the, Heylin Seed, the Ying-Ying Bird and Hannibal Roy Bean himself were all actually wrought upon the Earth as well. However, before any more damage could be done to the planet Earth itself, the very pure essence of all four of the world's pure elements immediately took on physical shape in order to oppose Lord Serpentius and his reign of terror and evil.
Now then, the initial forms that they all took were the forms of four uniquely colored celestial dragons and thus, they were quite literally the very first four Xiaolin Dragons in every possible way. There was the original Xiaolin dragon of the Water: the blue dragon, Tornabi; the very first of the Xiaolin dragons of the Earth: the green dragon, Tebigong; the original Xiaolin dragon of Fire: the red and yellow dragon, Hanabi, and last but definitely not least, the very first Xiaolin dragon of the Wind: the white and gray dragon, Storm. Now then, it was almost immediately after becoming physical in body that the four dragons all waged a veritable war with Lord Serpentius and his dark magic. It was a long and truly fearsome battle between the two sides, but, in the end, though, it was ultimately the Xiaolin Dragons' side that prevailed and they finally banished the evil monster from out of our dimension and sealed him away within another with the hopes of never having to see or deal him ever again. But, things were still not quite over or finished for the four Xiaolin Dragons just yet, seeing as they decided to not only begin to heal the land of Lord Serpentius' darkness and evil with their own purity and light, but to also teach the humans of this injured land their ways, so that they too could become one with elements as well. Although the Xiaolin Dragons' methods of teaching these humans their ways was actually a mixture of both harnessing the power of nature itself and mostly of the ways of the physical form of fighting and training, known then as the martial arts. But, regardless of all of that, though, this still gave rise to a brand new order of people, people who would soon go on to call themselves the Xiaolin monks and, if they actually reached that high of a level of training and discipline, Xiaolin Dragons, in honor of the beasts that helped them to get their order started in the first place.
However, it was not just the celestial type of dragons that have been a big help to the Xiaolin order. For you see, even though Lord Serpentius himself was a rather dragon-themed type of creature and he even referred to them as 'brother' and/or 'sister' from time to time, the initial earth-bound breed of dragons were also known to be good allies to the Xiaolin Monks as well. I mean, sometimes, they served as guardians for the Xiaolin order's scattered about temples, sometimes they have served as simple companions and means of transportation for certain monks, and sometimes they have even been known to act as the occasional advisor to the more high ranking masters and even mentors to certain new generations. This is actually all how the members of the family of Dojo Kanojocho became so acquainted with the Xiaolin monks in the first place and how Dojo himself became the resident mystical flying dragon guardian of his own Xiaolin temple. But, the initial evil and darkness of old Lord Serpentius himself could not be snuffed out altogether, I am sorry to say.
For you see, not only did his presence on Earth give birth and rise to both Hannibal Roy Bean and the Heylin Seed, but, even after he was finally gone, his dark influence gave creation to the Lao Mang Lone Soup, Sibini and even to Wuya herself. Plus, it was also actually due to his initially cosmic attempts to actually break free from his dimensional prison that Lord Serpentius also gave indirect birth to the Heylin Comet, as well as the initial circumstances that make Mala-Mala Jong's creation possible. And because of this, Lord Serpentius has a very deep connection to all things that transpire on Earth in the name of the Heylin side, just like how the first four Xiaolin Dragons also have a very deep connection to all things Xiaolin, especially in regards to the initial use of their signature Xiaolin elements. Everything is made to exist in some form of balance.