The Return of Harmony, Part 1: Introduction
Discord made his debut as the main antagonist in the Season 2 two-part premiere "The Return of Harmony". In his first appearance in "Part 1", Princess Celestia explains to Twilight and her friends that Discord once took over Equestria and caused chaos throughout for earth ponies, unicorns, and pegasi alike. Nobody dared stand up to his horrendous rule until Luna and Celestia discovered the Elements of Harmony and used them to turn him to stone, and reclaim the throne. Celestia explains that since she and Luna are no longer in connection with the Elements of Harmony, the spell imprisoning Discord has failed and he has escaped from his stone prison and stealing the Elements of Harmony, implying to have hid them in the Canterlot castle labyrinth. With nothing to keep his powers in check, he begins to wreak chaos throughout Equestria, turning clouds into cotton candy that move of their own accord and rain chocolate milk, and causing animals to become wild and automatically change shape.
When the Mane Six venture into the Palace Labyrinth, Discord magically steals the pegasi's wings and the unicorn's horns so that they would be unable to use their magic or ability to fly to "cheat" in the "game" he forces them to take part in to find the Elements, and separates them by raising sections of the Labyrinth's walls. Discord used representations of the cast's cutie marks, and subtly manipulates them into questioning the morality of their element, which drains them of their color and severs their connection to the element they represent, causing their personality to become their polar opposite. The one exception is Fluttershy, as nothing could ever make her doubt kindness, and Discord ends up having to corrupt her forcibly, bidding her goodbye with a frustrated "Arrivederci!" He eventually plays on Rainbow Dash's loyalty by showing her a vision that her hometown of Cloudsdale would be destroyed without her, and offers her wings back and a choice to either go to its aid, or continue seeking the Elements. This tricks her into flying out of the Labyrinth, breaking Discord's first rule that nopony is allowed to fly or use magic. Discord then causes the entire Labyrinth to collapse, and standing before the five remaining Ponies, gleefully states that he has won, and Equestria will now be thrust into eternal chaos.
The Return of Harmony, Part 2: Defeat
In The Return of Harmony: Part 2, Equestria is thrown into eternal chaos, and Discord points out that he never said the Elements of Harmony were in the Labyrinth. It is not until she returns home that Twilight realizes the answer to Discord's riddle was that they were inside a book at her house. With the Elements, the ponies (minus Rainbow Dash, who is replaced by Spike) attempt to use them on Discord, but failed. Twilight is however able to restore them by using her magic to show them images of past adventures. She does this with Rainbow Dash last, after which they confront Discord, who is still confident that they could not defeat him, and makes himself an open target. As the ponies' representation of the elements are restored, however, they use them on him in a similar style to Nightmare Moon, turning him to stone, this time with a look of horror frozen in his face.
Keep Calm and Flutter On: Beginnings of a redemption
Discord returns to begin his journey to redemption in Keep Calm and Flutter On. Celestia brings the stone Discord before the Mane Six and tells them she could make use of his magic if they could reform him. As a precaution, she gives them their Elements of Harmony, enchanting them so Discord cannot take them and hide them again. Twilight and the others release Discord from his stone prison. With a combination of Fluttershy's Stare and the threat of being turned to stone again, Discord doesn't do much chaos, but brainwashes some beavers behind the ponies' backs. Fluttershy (whom Celestia was most confident in) was the only one willing to give Discord a chance, and had him stay at her house. Discord does not act evil, intending to trick Fluttershy into eventually removing her necklace. He also consumes several pages from books holding reforming spells Twilight planned to use on him.
While Discord is having a dinner party with the Six, making objects come to life and cause chaos, Fluttershy says she and Discord were friends, which affects Discord as he never had a real friend before. When the corrupted beavers flood Sweet Apple Acres with their dams, Discord says he will fix this in exchange for Fluttershy's promise not to use her Element of Harmony on him. Discord breaks the deal and freezes the water instead of removing it. Twilight wants to turn Discord back to stone, but Fluttershy refuses, having promised Discord not to. When Fluttershy walks away, however, Discord realizes he could not stand losing his only friend and restores everything to the way it was.
Fluttershy shows Discord how important friendship was to him, and once he had it he didn't want to lose it. Discord also says, rather reluctantly, "Friendship is magic", the first time the line was ever spoken in the series. However, the episode ends on a bit of a wary note as while Discord openly says he'd never use his magic for evil, he quietly adds "Most of the time". Celestia also, rather practically, leaves the Elements of Harmony in Twilight's position, just in case. Discord overhears Celestia revealing her intention to Twilight and shows a face of concern, possibly because of the lack of trust they have in him or because it will make any future evil plan of his harder to pull off. Whether Discord will truly reform entirely with everyone else in the series or relapse into his old ways has yet to be seen.
Princess Twilight Sparkle
Discord's final steps toward redemption as well as his past arew revealed in flashbacks in the two-part fourth season premiere Princess Twilight Sparkle. Discord appears when the Mane Six summon him, accusing him of the chaos in Ponyville.
With Discord claiming innocence, the girls prepare to turn him back to stone. But Fluttershy stands up for Discord, saying that he is indeed reformed. Discord thanks his new friend "Shutterfly" while embracing Rainbow Dash. Fluttershy corrects him on name and pony. Twilight asks for Discord to help her find out who's responsible for the chaos, but he refuses, telling them to ask Zecora instead.
After Twilight witnesses Princess Luna's transformation into Nightmare Moon after drinking Zecora's potion, she sees all of her friends looking strangely at her. Discord informs her they are doing so because of all the "talking to Luna and Celestia" and crying she did while witnessing the fight between Luna and Celestia, openly mocking her for doing so. After drinking the potion again, Twilight witnessed the first confrontation between Luna, Celestia and Discord. In the vision, Celestia and Luna order Discord to stand down and stop causing chaos and destruction, but he does not take them seriously and ignores them, all while eating and tossing around a bag of seeds. When the Princesses prepare to use the Elements of Harmony on him, Discord begins to laugh uncontrollably and does not notice the Princesses using the Elements' powers on him and is turned into stone.
Later, Discord is still enjoying the mess in Ponyville and even enjoying the suffering of others, watching Cherry Berry and Comet Tail struggle from vines up until Twilight arrives and scolds him, telling him to help them, which he does. He asks Twilight what she's doing back already and Twilight tells Discord she left her friends behind because she needed to. Discord began taunting Twilight, saying that he was shocked that she would leave her friends in danger. Discord's words get to Twilight and she leaves to save her friends. Discord waves as she leaves.
Later on, after she gave up the Elements of Harmony to the Element tree saving Equestria, Discord congratulates them and asks how they did it. They say they gave up the Elements of Harmony, Discord sees this as a chance to relapse, but Fluttershy warns him of the consequences, meaning he'll lose his friends. Discord agrees to clean up the mess, but he won't do the Windows. Applejack wonders why all this happened to begin with, and Discord mentions out loud that the planted seeds that should have sprouted long ago. Twilight uses Zecora's potion to see that Discord really did his Plunderseeds that were supposed to steal the Element Tree's power and capture the princesses, but the tree's powers were too strong. Twilight scolds Discord again saying they could have used this information, but Discord explains it was to teach Twilight a valuable lesson about being a Princess.
Discord visits Ponyville claiming to be suffering from "blue flu" and asking for help from his pony friends. With Fluttershy away on a trip to observe the Breezies, it ultimately falls to Twilight Sparkle and Princess Cadance to care for him while he is supposedly ill.
Eventually, the blue flu turns out to be a deception, as Discord claims that he was worried Twilight Sparkle was not really his friend and concocted an elaborate test to determine if she would really act like a friend to him. He is overjoyed to see that she chose to help him, even though it interfered with her time with Princess Cadance. Ironically, Discord becomes infected with a real disease when a Tatzlwurm sneezes on him. He is placed in a quarantine bubble in Fluttershy's cottage where his Pegasus friend can care for him. During his visit, Discord reveals that he and Fluttershy have been keeping a correspondence.
Twilight's Kingdom: Betrayal, forgiveness, and final redemption
Discord's redemption has a bit of a backslide in Twilight's Kingdom. In this two-part episode, Celestia seeks the help of Discord to fight Lord Tirek instead of Twilight, as he could sense magical imbalances. Delighted with the news, Discord arrives to gloat to the ponies. During his, Discord reminds them of how they haven't opened the Tree of Harmony's chest yet, revealing his interest in the chest's contents. Before leaving, Discord gives the Mane 6 back the journal they've been writing in, with bookmarks on specific pages. He then asks Fluttershy if they are still going to have tea later, stating that he will bring the cucumber sandwiches before opening a door to Tirek's current location. While re-reading the journal, Twilight realizes that the pages Discord bookmarked were about the times they had to represent their element in a difficult situation, changing some-ponies' life in the process, realizing that Discord was actually trying to help them, in his own way.
In the alleyway that Tirek was residing in, Discord disguises himself as a unicorn and successfully attracted Tirek. Recognizing him, Tirek commends Discord on his escape from his stone prison, only for Discord to bind him with shackles, Tirek believing that someone as powerful as Discord wouldn't want to share power. However, Discord informs him that he was actually re-imprisoning him for his friends, who required him to do so. Seeing this as his chance, Tirek manipulates Discord into thinking that his new friendship was just a new form of prison, as he had to give up his natural destructive nature in order to stay in their good graces and convinces him that, if they worked together, he would have something far more valuable that friendship; his freedom.
Thinking it over, Discord decides to join Tirek and help him steal all of the magic in Equestria. When the three princesses get word of this, the immediately summon Twilight and informed her of what Discord and Tirek have done. First, they go to a magic show where Discord teleports Tirek in front of a crowd of helpless unicorns and absorbs all their magic, next, they attack the Wonderbolts and Pegasi and steal their flight as well, and finally, they go to Appleloosa and steal the strength of the Earth Ponies and presumably go to multiple other locations and steal the magic of everypony there. With no other options, the princesses give all of their magic to Twilight, as Tirek was not aware of her existence, and Discord sensed the magical imbalance, but decided not to tell Tirek. He and Tirek effortlessly defeat the royal guards and a weakened Shinning Armor asking him why he would do something like this, only for Tirek to tell him to go have fun while he dealt with the princesses, with Discord looking on with a sadistic grin. After Tirek banishes the princesses to Tarturus, Discord changes all of the stained glass windows to images of him and Tirek causing mayhem. When Tirek sees the window displaying the Alicorn Twilight, he angrily demands why Discord didn't tell him that there was a fourth princess, only for him to state that he would after he knew he could truly trust Tirek, and now that he can, he tells him about where she lives and her friends. As a sign of gratitude, Tirek gives Discord a medallion that was given to him by "someone close to him."
After getting them to Ponyville, Discord sadistically imprisons Twilight's friends in a cage, informing them of his betrayal. Surprisingly, Discord looks away in shame as Tirek steals their magic, although he instantly goes back to his evil behavior after he's done. Almost immediately, Tirek uses his newfound strength, betrays Discord and steals his magic, stating that the medallion he gave him was given to him by his brother, who betrayed him, and that the medallion, much like his brother Scorpan, was completely worthless.
After their legendary battle, Tirek forced Twilight to choose between her friends and her magic, with her friends stating that they're not worth it, although the now remorseful Discord states that Fluttershy was worth it. After Twilight decides to exchange all her magic for all of her friends, including Discord, he gives her the medallion Tirek gave him as a symbol of their 'friendship'. The necklace turns out to be the final key that unlocks the chest which contained rainbow power. After Tirek is defeated, everyone, including Discord, gets their magic back.
By now, Discord has officially joined Twilight's group of close friends, although he didn't end up receiving a throne like all of her other friends.
Make New Friends but Keep Discord
What About Discord?
The Cutie Re-Mark: Alternate timeline
The fifth alternate timeline created by Starlight Glimmer has Discord still evil and in power, chasing Celestia and Luna around on a unicycle. This timeline along the others that were created by Starlight Glimmer were all erased when Twilight Sparkle convinced Starlight Glimmer to let Rainbow Dash do her Rainboom and history was restored to its original state.
Dungeons & Discords
Discord joins Spike and Big Macintosh on their guys' night when the Mane Six leave to Yakyakistan. He looks forward to a night of partying and dancing, but it turns out to be an evening of playing the fantasy role-playing game Ogres & Oubliettes, much to his disappointment. Throughout the evening, Discord tries to steer things toward more enjoyable activities, but Spike and Big Mac insist on playing their game. Discord's disinterest in the game and frustration eventually drive him to create a real-life version of Ogres & Oubliettes. However, his efforts are met with Spike and Big Mac's cold reception, and he leaves out of embarrassment when he discovers they only invited him on their guys' night because they felt sorry for him. Spike and Big Mac soon invite him back to give him a second chance, and he joins their role-playing game as an Archer-class character.
To Where And Back Again
Discord teams up with Starlight Glimmer, Trixie and Thorax to save their friends - particularly Fluttershy - when they are captured by changelings. Discord's magic is disabled in the Changeling Kingdom due to the properties of Queen Chrysalis's throne, forcing him to navigate the castle without teleporting. While in the castle, Discord has frequent arguments with Trixie because of their clashing personalities. On their way to the throne room, Discord distracts a detail of changeling guards with a stand-up comedy act, but he is eventually captured when a group of changelings all disguise themselves as Fluttershy. After Chrysalis is defeated, Discord joins the ponies in celebrating the Sunset Festival in Our Town, and offers to improve Trixie's magic act with his chaos magic. When Trixie claims "When pigs fly!" he snaps his fingers and creates to flying pigs and chases Trixie through the town on them.
Discord receives an Equestrian Pink Heart of Courage for saving Equestria alongside Starlight Glimmer, Trixie, and Thorax. He also puts intense pressure on Twilight to come up with a plan for Starlight now that she has learned all of her friendship lessons, and discloses her decision as a "surprise" to her friends before she can figure out what to do. In the end, he is disappointed when Twilight settles on graduating Starlight, revealing his hope that she'd send Starlight to his realm as a roommate.
Discord hosts a tea party in his home realm for Fluttershy to thank her for all the times she hosted a tea party for him at her cottage. Fearing that she will be uncomfortable there, however, he decides to change both his home and himself to be normal. Unfortunately, not only is Fluttershy disappointed in the party's lack of excitement, but Discord's new persona is so contradictory to his inherent nature that it begins to destroy him. With Fluttershy's help, Discord embraces his chaotic ways and stops fading away.
The Break Up Break Down
A Matter of Principals
Discord suddenly appears behind Starlight and Spike to their amazement. He claims to come to temporarily run the school in the absence of Twilight until Spike points out to him that these Starlight who was appointed in charge of the school. Exasperated, the Draconequus proposes modifications to the rule but Starlight declines and specifies that she does not need its help, upset Discord answers that they will do if it changes its mind before teleported.
Later, Starlight and Spike go to the headmaster's office but discover Discord redecorate it in his chaotic manner. He again offers his ideas little orthotoxe for the school but Starlight still declines and pushes him to the door asking him to go home, only Discord let him know that he also hired temporary teachers for the friendship lesson. Unfortunately, the new teachers prove to be bad enough to teach the friendship that provokes agitation and disorder in the school. Starlight tells Discord that it's all his fault, but Discord reminds him that she's the one in charge, Starlight, even more upset by the selfish behavior, asks her to leave again, Discord turns into a leaf and wants to go out by the window growling that he just wanted to help.
Of course the next day, Discord does not give up and infiltrates the Trixie magic class that Starlight has hired as a new teacher. After interrupting Trixie with a banana phone, he pulls out of the unicorn hat a Ursa Major that scares the whole class. In the field of Sport, he masquerades as the gym teacher and makes appear a bugbear that makes the students run but Starlight chases the creature before it hurts someone. An angry Starlight screams at Discord that she's tired of him and that his dangerous action stops now. Dicord not impressed, refuses with provocation and Starlight gives him an ultimate warning until Spike tries to calm the situation by reminding Starlight that Discord is her friend but Starlight says he does not act as a friend. Spike asks Discord what his problem is and Discord answers that his problem is that Twilight is named an incompetent and power-hungry unicorn in charge. With this insult of too much, Starlight launches a huge wave of magic that seems to annihilated Discord to the horror of the students until Starlight reassures them explaining that she has just banished Discord from school forever.
Discord, however, is still able to come to school in spiritual form. He terraces the students during their treasure hunt with the artifacts they were supposed to look for. While the students are surrounded by the inanimate objects, Starlight arrives and Discord shows up. Starlight confronts Discord and tells him that he can not continue to cause chaos in the school but Discord replies that he can and will continue. Much to Discord's surprise, Starlight tell him she's sorry before restoring his physical form. Having finally understood why Discord did all this, Starlight apologizes for never having invited him to school before and suddenly made Discord feel excluded. Both make peace and Starlight offers him the vice headmare position which he accepts with pleasure.