Once upon a time, there was an amazingly powerful Unicorn named Starswirl the Bearded. He was quite possibly the strongest Unicorn in all of Equestrian history, rivaling even the Princess' themselves. He was the creator of hundreds upon hundreds of spells, charms and even curses. Starswirl was renowned and famous for his use of magic in ways no one, not even Celestia herself, ever thought of using. He created a spell to travel through time itself, if only but for a few moments. A curse that could change the Cutie Marks of any Pony, completely altering their memories and memories of Ponies around them. But even with the most famous of all Unicorns, there are secrets that are not meant to be know to everypony. This is that such secret.
One day whilst he was in Canterlot library he witnessed a mare with two young foals, sitting at a table and reading as a family. He felt a saddening tug at his old and withered heart at this, realizing his own life. He had spent his entire existence devoted purely to magic, never leaving to learn or gain friendships nor affection to other Ponies. He was Equestria's greatest magician with everything in which he could ever want. All, except the embrace of a family he made and raised himself. This filled the elderly colt with despair and depression, leading to several months, nearly a year, of inactivity. In his time of hiding, Starswirl was secretly creating what he believed would be perfection. The purest heir. The greatest son Equestria could create.
He studied and practiced his own spells and charms, building them into one large cast. He built his creation from the remains of multiple creatures, keeping the head that of an equine. The wings of a bat and an eagle, legs of goat and reptile. Body of a dragon-esque creature and arm of a lion and talon of a hawk. This composite creature was to resemble all of the beings in nature, attaching him to Equestria. After many, many months of planning, trials and, of course errors, Starswirl believed he finally created the perfect spell to both bring his heir to life and fill him with magic equal or even greater than his own.
Sadly, there was one thing that the great Unicorn did not take into consideration when he performed this spell. His months away from Ponies has driven him into near insanity, making his magic unpredictable, rectless, even chaotic. Starswirl channeled all the power he had into this spell, drawing the essence of all life into his son. Unfortunately, the spell did work. A little bit too much that he expected it to. The creature was brought to life, but he did not act as Starswirl planned him to. His heir was irrational, using the magic he was filled with to conjure and alter reality itself. The elderly magician was quick to charm his dwelling so the creature could not escape, but he was weak. From the spell to the weeks of isolation, his abilities dwindled to a near spark while his composite son grew stronger every day.
Soon, the bearded Unicorn could no longer hold back his son and the Draconequus was released onto Equestria. It did not take long for the creature to alter all of the land to his control. The Princess' were not prepared, and the world was sent into a state of eternal chaos. In a period of panic, Celestia went to Starswirl for assistance for this problem unknowing of he creating this, as the Ponies were referring to, demon of Chaos. Sadly, she found the old wizard near death in his housing and unable to help.
For a number of years Starswirl was in no state to help, being stuck in a comatose state. During this time, the composite monster of chaos wreaked his disharmony to point he grew tired. When gathering hear of his creatures current state, the frankenstein of Starswirl quickly turned to his side. Feeling a new sensation in their chest, Starswirl's son decided onto returning what was taken from his father those years ago. He place the lions paw onto Starswirl's head and force a portion of his magic back into him, effectively bringing the Unicorn out of his coma like state. When Starswirl finally awoken he found no one in his dwelling, but could feel a faint sense of weakened magic around his bed and himself. He knew all to well what had happened, and even more on what to do now that his creation, his heir... His son, was now weak.
He made immediate haste to Canterlot Castle where the Princess' were still attempting to hold of the approaching chaos. He did not tell how he came up with it, but he presented a set of enchanted stones with more than enough power to defeat his heir. He called these stones the Elements of Harmony and he made very specific modifications to this weapon of magical disturbance. He made it to where, no matter the enemy or situation, the Elements could not destroy. Only alter or relocate to a place where they would not cause any harm. The Princess' used these Elements to turn the Draconequus into a living statue where he was presented in the royal gardens for all to see. And see one Unicorn did, as Starswirl visited his son in secret everyday of every year he remained alive. He knew what he created was an abomination to all of Equestria, but Starswirl still held in his heart that one day, he never knew how long, his son shall be reformed.