Princess Eris

Princess Eris was the Lord of Chaos of her dimension and the cousin of Discord. A powerful and foe most wicked, Eris doesn't view chaos in the same jovial way her cousin does, but instead embraces the more practical effects of chaos; one where the strong may do whatever they want to the weak. Eris had no moral code to speak of, not caring that her antics could destroy entire worlds and dooming all within.

History
Like Discord, Eris is most likely millions of years old. Being his cousin, Eris is directly related to him by "blood", or whatever genealogical system members of her race belong to.

At some point in the past, Eris conquered the Equestria of her world with the aid of the Pony of Shadows. Together, the two reduced Princess Celestia into a bestial and savage being, which Eris adopted to be her own "pet". After Princess Luna and Stygian broke into her palace, Eris trapped Luna in a cage and used the Staff of Sacanas to absorb her power, reducing her into a powerless state. Eris's plan was a simple one, to use the power of Luna to bring untold chaos to the world. With control over the moon, Eris would be able to control dreams and nightmares and would use that very power to make it so ponies would never sleep ever again.

Personality
Eris is a haughty and unbelievably cruel Lord of Chaos without the jovial sense of fun Discord possesed. While Discord would be content with making simply having fun at others expense, Eris instead sought utter destruction. She didn't just dispose or annoy the monarchs of her world, she turned them into mindless, bestial slaves loyal only to her and created a world where the wicked do whatever they wish while the good are locked away, never to be seen again.

It's unclear whether or not Eris's appearance is what she truly looks like or not, given that she's supposedly related to Discord yet appears as a completely species. Nontheless, she appears as a tall, multi-colored anthropomorphic parrot, resembling those found in the Mysterious South. She sports a pink base with purple, pink and yellow "hair" and pale green eyes. She wears a long, skirt-like piece of attire with an even longer cloak. Her skirt resembles peacock feathers. Despite this, while her cousin despised any form of royalty or rulership, she openly refers to herself with titles of authority, such as "Princess".

Like her cousin, Eris is an amalgamation of several different animal parts, though is much less obvious than her cousin. She has ram-like goat horns, bat-like wings and human-looking arms and hands.

Discord
Eris is the cousin of Discord and appears to be loathe her cousin for his jovial and well-humored personality. She instead desired him to use his power for what it was truly meant to be used for, to cause pain and destruction upon the world.

Princess Celestia
Eris considers Celestia to be her "pet" and treats her like her possession. She trained Celestia to be a like an attack dog, using her to attack would-be introduces and scolds her whenever she fails. As Celestia no longer has any free weil, Celestia does as she's told with no questions.

Powers and abilities

 * Chaos manipulation: Eris has the ability to manipulate chaos itself, which allowed her to warp her world in her twisted image.

Possessions

 * Staff of Sacanas

Behind the scenes
Eris first appeared in the the, but her existence was teased at in the first promotions of the comic, granted under vague names such as a "great evil". Eris's name is derived from "Eris", the Greek goddess of chaos and like her cousin, her design was based off numerous animal parts to give her an inherently chaotic look.

Appearances

 * (mentioned)
 * (mentioned)