As you can see, the rumors of my death have been greatly exaggerated. 
It's true I've been getting a bit distracted from the Legends of Lore lately, but I have good reason, I promise!
Starswirl and Discord · 4:42pm Apr 8th, 2015
Personally, I'm of the opinion that Starswirl and Discord and not connected in any way. However, since them being connected in some way is such a popular fan concept, I decided to jot down my own idea on the matter. Enjoy.
During the early years of Celestia's rein, Starswirl was her devoted teacher and friend. He came to love Celestia, and one day professed that love to the still blank-flank Princess (who, lets not forget, at this point was still far older than Starswirl). Celestia cared for Starswirl but could not bare the thought of letting herself love someone who's life was but the blink of an eye to her long years, and so she told Starswirl they could never be together. The dismayed Starswirl through himself into his research. In an act of love and desperation, he attempted the creation of a spell to change the very threads of fate itself, to alter destiny. Celestia begged him not to attempt it, but Starswirl would not listen. He cast his final spell, and failed, dying in the attempt. Or so everyone believed. Starswirl's very being was ripped apart before Celestia's eyes, his every cell torn asunder as his failed spell dashed him against the intricately intertwined web of destiny and reality. However, not all of Starswirl was lost. His mind was shredded and scattered, but it still lived on. He was all around them now, in the air, in the water, in the very earth. So damaged was he though, that not even his own mind knew it yet lived on. Decades after Starswirl's death, his shredded mind began to slowly pull itself back together. The process took hundreds of years before he was even a shadow of his former self, but even then, he was still just consciousness and had no form. His memories, his identity, everything had deserted him. He was now simply a nameless, shapeless collection of thoughts. For hundreds of years after, he endured this existence, the silence, the solitude, the utter emptiness, and it drove him mad. Through the years, he learned to focus his will to affect the world around him, and after great time and effort he was able to produce a corporeal form that could be perceived and interact with the world. This form was greatly corrupted and twisted by his madness however, and held no resemblance to his old self. And thus, Discord, the spirit of chaos and disharmony was born.
Nice theory.
Thanks. Been a while since I've seen you around.