Accord

"(All: DISCORD?!) Good evening everypony. (Fluttershy: Discord? Are, are you feeling okay?) Oh I feel quite fine, but i'm not sure i'm Discord!"

- Accord first emerging "With my magic, I can make every pony agree to work together! No arguments! No disagreements! I could ensure that every pony does precisely what they are supposed to do, with no distraction or delay! (Starlight Glimmer: Accord, you can't control ponies like that. My village was horrible! Everypony wanted to escape!) Then I will make sure they do not want to escape! You cannot make every pony the same. But I can make them all think the same way!"

- Accord to Starlight Glimmer "Imagine my friends. Imagine an Equestria ruled by order."

- Accord after revealing his true nature Accord, the self proclaimed bringer of order and harmony, is the main antagonist of the seventeenth story arc in IDW's My Little Pony comic series: Chaos Theory (issues 48-50).

Accord was created during an astronomical event called the Cosmic Convergence when it somehow affected Discord and turned him into an egg which eventually hatched out Accord, a being of pure order instead of chaos.

Accord, wanting to bring order to Equestria and give his chaotic counterpart a better reputation, helped out the Mane 6 and various other ponies until it was revealed that he actually intended to mind control all of Equestria into thinking the same as each other in order to create true harmony.

Issue 48
When the Mane 6 attempt to view the Cosmic Convergence event, Discord tags along with them and attempts to become the center of attention, only to be scolded by Applejack for pulling another one of his attention grabbing stunts and disturbing the crowd of other ponies there. Discord then teleports away when he realizes he isn't wanted, leaving a large cloud of smoke behind.

During the Cosmic Convergence, Starlight Glimmer notices a strange green glow and urges the rest of the Mane 6 to check it out. The Mane 6 then recognize the source of the glow as an egg that looks and smells like Discord and they bring the egg back to Twilight's Castle to decipher what the egg contains. While the Mane 6 are examining it, the egg burst open and reveals a much more professional, well dressed and dapper version of Discord. The Mane 6 are baffled by Discord's appearance, but he explains that the Cosmic Convergence transformed him into a being of order instead of chaos and that, while he technically is Discord, he doesn't feel like him in the slightest, which results in Twilight renaming him Accord; the opposite of discord.

The next day, the Mane 6 show Accord around Ponyville, shocking various citizens. Accord continues to explain that, unlike Discord, who used his powers for his own benefit and amusement, he only wants to use his powers to help others and seeks to have a better reputation than Discord did. Accord also explains that, since he has no idea why he transformed from Discord into Accord, he doesn't know when or if he'll ever turn back into Discord, although Applejack states that, since he is far more polite than Discord ever was, she wouldn't mind him staying around. When Starlight asks about how his magic works, Accord explains that his magic organizes, harmonizes and unifies things to the way they should be, fixing a pony's broken produce wagon as an example.

Rarity then has the idea to have Accord help build the Ponyville Motel, which had been under construction for years yet was never finished due to a design disagreement between the building's two main architects. Under the instructions of Mayor Mare, Accord uses his powers to try and fix the chaos, however, he uses his abilities to mind control the architects into agreeing on a design, only for Mayor Mare to tell him that she wanted him to use his magic on the building, which he happily does.

That night, the Mane 6 express their admiration for Accord (although Fluttershy still doesn't know how to feel about him), but Starlight tells Twilight that she is concerned about Accord due to his willingness to use mind control to fix problems, which is something she used to do in the past, but Twilight tells her that it was only a mistake and that Accord means well.

The next morning, Princess Celestia and Princess Luna invite the Mane 6, Starlight and Accord to dinner to discuss Discord's transformation into Accord. At the restaurant, Accord informs the princesses that he intends to bring order to Equestria, however, Starlight brings up her concerns about Accord's use of mind control. Accord then states that he is surprised that Starlight is disagreeing with his methods, considering she has used them in the past, and that he intends to simplify the process, bringing concern to Twilight and Celestia. Accord continues to talk about how he could make the citizens of Equestria all perform their duties without disruption and delay, explaining that, while the citizens of Our Town hated being there and wanted to escape, he could make it so the ponies of Equestria would never want to leave his control. Accord then begins to sent a mist through the restaurant that brings all it's staff and customers under his control, horrifying Twilight and her friends. Accord then states that, since he can make everypony think the same way, he could most likely do a better job at ruling Equestria than Luna and Celestia. Accord then attempts to blast the Mane 6, Starlight, Celestia and Luna with his magic, but Celestia and Luna block his attack using a force field. Accord then finally tells the nine ponies to imagine an Equestria ruled by order.

Issue 49
At the beginning of the issue, Accord continues to try and sway the Mane 6, Starlight, Princess Celestia and Princess Luna to no success. Starlight tries to talk Accord out of mind controlling others, but Luna tells her that he will not listen to reason and quickly realizes that Accord's magic is spreading, putting all of Canterlot and potentially Equestria at risk.

Twilight then formulates a plan; while Celestia and the others evacuate Canterlot, she and Princess Luna, who has entered Discord's mind before, will use a spell to sent themselves into Accord's mind to prevent him from mind controlling ponies.

Twilight and Luna transport themselves into Accord's mind and find that it, much like Accord himself, is completely orderly and has no trace of Discord's personality at all. Twilight also deduces that a spell must have been involved with Accord's transformation, meaning that someone wanted to change Discord into Accord. Twilight and Luna then dive deeper into Accord's mind and find that the depth of his mind are represented as a boring, colorless office. Twilight and Luna soon find that their wings and magic don't work inside the office and that all of the Accords managing the real Accord are too busy to help them.

Meanwhile, Accord continues to brainwash the citizens of Canterlot and reveals that he is inside the hearts of everyone he controls, manifesting his face over all his controlled subjects in order to confront Celestia. When Applejack and Starlight tell Accord that his methods of trying to create order are not just, he merely states that he is trying to accomplish the same goal as Celestia; bring order to Equestria by eliminating chaos. Accord attempts to convince Celestia to ally herself with him, only for her to angrily teleport Starlight and the Mane 6 away from him, resulting in Accord's subjects trying to chase them down.

Back in Accord's mind, Twilight and Luna become frustrated with trying to navigate the office, as everything looks exactly the same. The two Alicorns decide that the best course of action is to look for any traces of chaos in Accord's mind, and, upon finding a snow globe, Twilight realizes that Discord is inside of it and smashes it on the floor, releasing him while covering the office in snow. Upon Discord's release, Twilight asks him who changed him into Accord and Discord revealed that he changed himself into Accord upon realizing that his personality would never allow him to truly fit in with the citizens of Equestria. Discord also reveals that he cannot turn back into himself as he is only a small portion of Accord's body and that the only way to get rid of Accord is to convince him to turn back into Discord. Twilight, Luna and Discord are then backed into a corner and surrounded by the numerous Accords that inhabit Accord's mind.

Back in the real world, Celestia, the Mane 6 and Starlight reach the edge of Accord's hypnosis field and begin to evacuate Canterlot. Celestia, Starlight and the Mane 6 look over head to see Luna and Twilight now under Accord's control.

Issue 50
Coming Soon!

"After Discord left the star-gazing party, he was affected by the magic of the conjunction. Somehow, it... changed him. I am the result. I was Discord, but now I am something else. (Twilight: So...what are you?) I am Discord's opposite! Where he promoted chaos and confusion, I encourage order and sense! Instead of mischief and trickery, I create organization and unity! So I don't know what I am! I was Discord - I have all his memories and I know all of you - but I think I am someone else! (Twilight: So you're the opposite of Discord, huh? Well, the opposite of Discord is Accord, maybe we should call you Accord!) A very appropriate appellation indeed!"

- Accord explaining himself to the Mane 6

Issue 49
"Join us Princesses. See how wonderful things could be when everypony agrees!"

- Accord with mind controlled ponies "(Starlight Glimmer: Accord's magic is spreading, and quickly!) It's not just my magic, Starlight Glimmer, it is me. I am here, in every pony! I and the unifying principle of order! I live in the hearts of all ponies who desire order! And order we shall have."

- Accord while manifesting his face onto other ponies "(Applejack: This ain't order! You're just taking over ponies' minds! Starlight Glimmer: Accord please! This isn't right!) Not right? But we are merely trying to achieve the same goal as Princess Celestia! (Celestia: WAT.) You and your sister are trying to bring order to Equestria! After all, when you battled Discord long ago, you were trying to defeat chaos, were you not? You were trying to create order where there was none! We are allies Princess! Let us control Equestria together!"

- Accord to Celestia, Starlight and Applejack

Trivia

 * It is possible that Accord is not truly as powerful as Discord is. While Discord is shown to have the power to bend reality to his liking on a whim, Accord is never shown with these capabilities, as, instead of just warping the minds of every pony in Equestria (which, considering his god-like power, he could certainly do) he chooses to instead use a rapidly growing bubble that puts creatures under his control. Although unlikely, it is possible that Accord actually never uses all of Discord's god-like abilities because they would interfere with his desire for order.
 * Much like Twilight Sparkle, it is possible Accord has some kind of OCD.