Discord sat in a chair made by him in the middle of everfree forest. He cursed looking around the untamed landscape. He could never do what he wanted... his very freedom was always keep in check by Celestia and her student the new Princess Twilight Sparkle. He was so bored out of his very mind. He Stood up with anger after a few moments. "You know what screw this... there has to be somewhere fun.... wait." He got thinking "Somewhere.. perhaps another universe?" He asked. He knew other realities exist. However most of them the ponies where quidpedal beings. He waved his hands and pointed in the air with his magic at a single point. A portal opened up as space and time bent to his very will. The gateway to another universe was opened as he passed right though the hole in reality.
(Gender flipped reality)
"I hate Helios, and his stallions." Eris said as she sat on a tree in everfree forest. The goddesss of Chaos was bored out of her mind. "I wish something would happen." Cue a portal opening up in the forest. Eris moved back in shock. Walking though the portal was... a bipedal being who looked almost like a gender flipped version of herself. The portal closed right behind him as he passed though.
"At last.... I'm free form Celestia." He said to himself. He sensed something. A being of Chaos as powerful as himself. Appearing in a flash was Eris.
"Well what do we have here?" She asked with a smile floating in the air.
(A few minutes later)
Eris and Discord had talked about there universes and there lives. They had a lot in common when they though about it.. One) They had been forced into there position by there respected Sun Butts, Two) They like chaos. Three) They wanted freedom.
They both laughed at this. "So if we do not like are position do you think there may others like us? Others who have to deal with Sun Butts control." Discord said to Eris with a laugh. They stopped laughing after this. The two of them blinked for a few moments.
"Lets do it." Eris said.
(Some Other Universe)
A portal opened up as Eris and Discord came out. They saw a reality with quidpedal ponies each with colors switched. How did they know this you ask? They saw Fluttershy flying by. Fluttershy was pink with a yellow mane. The two other them used there senses to locate there counterpart. In a flash they found this universes Discord trapped in stone. The two channeled there magic into the object as it slowly cracked open. The stone slowly cracked and the Discord of this universe was freed. "I'm freed?" He asked himself confused at this development. He felt a wave of Chaos wash over him then he was freed.
He looked as he saw to others like him. "What the chaos.... you both look kinda like me!" He exclaimed. The two looked at each other then went on to inform there counterpart.
(One explanation and the Next Reality later)
A flash they entered into a new reality. In a flash they located there counterpart. In this realities Everfree forest a very muscular Discord was punching, tossing, and braking the trees, rocks, and animals in his way. The reason for this very destruction was very simple. He was trying to end his boredom and not using his chaos and his anger at those ponies. A few flash's appeared around him was a surprise. The beings who appeared was a even bigger surprise in itself. "Well this is a surprise." This Discord said.
"Yes it is to each one of us." Eris said to this realities Discord.
(Next reality)
A flash the group appeared in a new reality. The newest change however was the statue of there counterpart in this universe. The four stared at his statue with a look of slight perplexity "An Alicorn? So this realities Discord is a Alicorn" Eris asked in a bit of surprise at the development. Indeed this Discord was a Alicorn like Celestia, Luna, and Twilight themselves. "Well then the Multiverse is a big and strange place." She reasoned for this it was not very hard for them to ignore this change. They saw only a being of Chaos.
They soon set him free as well. "I'm free? I'm Free!" He yelled in happiness. His horn glow with Chaos magic. He son noticed the others nearby him. "Who are you all?" Alicorn Discord asked.
"We are you." Anthro Discord said with a smile.
(somewhere else)
In a unknown place the group of Discords across dimension where meeting, talking about there lives there advantures and realities. However they where also planning revenge. Revenge against there enemies and there freedom. "So we all seem to have the very same problem." The Alicorn Discord said looking at his counterparts it was strange to see here forms given who he was.
"Indeed, we are all either imprisoned or freed but keep under control." Eris said summing up all there shared history. The biggest thing they all shared.
Muscle Discord punched his fist into his hand. He looked ready for a fight "Well we got enough power to do whatever we want now!" He said, "Least go take down are enemies together!" He said.
Color flopped Discord nodded at his counterparts statement. Giving him a clap of approval. "He's right we always been defeat by ourselves, however together no one could stop us." He said with a devilous smile.
Anthro Discord held his hand out. "Together." He said. The others looked t him. "Lets do it a Alliance of Chaos." The Discords thought it over for a moment. Soon they placed there limbs together.
"Lets do this." Eris said to everyone.
"Chaos... Forever!" they all said as one. Unknown to the Multiverse this was the dawn of its first multiverse Alliance, and Chaos was now united!