Discord (Friendship is Magic)

Discord was a lord of chaos who is, at least, millions of years old. As the possible embodiment of chaos in his dimension, Chaos is an immensely powerful and unpredictable being. While ultimately on the side of good, Discord was once the greatest villain ever faced by the lands of Equestria. In spite of this, Discord was never truly "evil" per say, he simplylacked compassion for others and did what he desired without comprehending any consequences.

Earliest known history
The actual "early life" of Discord is unknown and given his nature, was probably abstract and chaotic. According to Accord, beings of his level of existence existence as the underlining principal of whatever they embody, meaning Discord is likely the very embodiment of chaos, at least in his dimension. It's unknown whether or not Discord created the Chaos dimension, if the Chaos dimension created Discord, if they were created by an even greater being, or if they existence simply came into be someday, but whatever the case may be, Discord and the dimension are deeply connected.

Discords earliest known activity dates back several millions of years ago during the Age of Dinosaurs. There, he befriended a gentle Butterdragon named Hubert. Much later in his life, Discord became well known in Anugypt, gaining the hatred of King Anubis and love of Baast in his adventures there, whatever they entailed. At one point much later in his life, he appeared at Vorak's castle in the Infernal Lands during Prince Tirek's punishment.

Eris
Discord has a cousin named Eris, the princess of Chaos of her home dimension. It appears that the two never got along, with Discord being more jovial and playful while Eris was more destructive. Eris considered Discord a fool for wasting his powers on having fun, rather than destroying.

Cosmos
Discord once had a relationship with the entity Cosmos. Cosmos was an abusive lover towards Discord, and a rotten individual in general. While Discord wanted to use his powers for fun at the expense of others, Cosmos wanted to burn things, destroy things, to hurt others. Though proudly considering himself a villain, even Discord was morally against Cosmos's action and attempted to oppose her.