The story of the demonic centaur, Lord Tirek from My Little Pony: Friendship is Magic.
Along with his brother Scorpan, Tirek used to be one of the princes of their old kingdom. Their land was ruled by their parents, the Centaur King Vorak, and the gargoyle Queen Haydon. Despite their fearsome appearances, Vorak and Haydon were benevolent rulers who wanted peace with Equestria. They did their best to guide their children and keep them on the right path, but while Scorpan took after their examples, Tirek was shown to already be a delinquent who constantly got into trouble at a young age. Because of this, his father King Vorak disapproved of his behavior and actions, which caused Tirek to develop an intense hatred for his father. Tirek seemed indifferent to his mother, though it's mentioned in "Frenemies" that he did genuinely love his grandmother. Tirek was a prodigy among his land, born with more magic than any other being in their kingdom, though his father was fearful of this due to the fact that he could sense a thirst for power in Tirek, believing that Tirek would one day try to overthrow him. At some point in time, Tirek started meeting with an old evil centaur wizard called Sendak the Elder, and became his protegee.One day, Tirek and Scorpan went to visit Sendak. Though at first Scorpan said they had to return to the castle because their parents could be worried for them, Tirek ignored Scorpan and entered Sendak's home. Sendak told Tirek everything about pony magic and how he captured a unicorn when he traveled to Equestria. Sendak further revealed that there was a spell that would allow him to drain magic from other beings and use it to increase his own power, and that he was planning to do this with the unicorn he captured, though not at the exact moment. Supposedly, Equestria had more magic than any other land, and draining all of the magic from the land would make someone an "indominable force". Sendak realized that Tirek wanted to drain the unicorn's magic for himself, but he informed Tirek that he was too young to properly perform the spell at the time, telling him to wait until he was older.
Tirek and Scorpan returned to the castle where their parents, King Vorak and Queen Haydon were arguing until they enter on. That night, Tirek and Scorpan talked about their parents relations with them and when everyone went to sleep, Tirek went out the castle to find out more about pony magic. Once in Sendak (who was taking a nap)'s home, Tirek tries to make the same ability that Sendak used to steal the pony's magic until Sendak woke up just to see how Tirek's spell of absorbing magic just causes a great explosion that traps Sendak under a pile of rubble. Sendak asks Tirek for help, but he abandons him and sneaks back to the castle.
The next day, it is revealed that Sendak was rescued by Vorak's guards, but was sentenced to work in the mines for the rest of his life as punishment for kidnapping the unicorn. Vorak asks Tirek where he was the night when the explosion happened and Tirek explains that he never left the castle. However, his father doesn't believe him and confines Tirek along with Scorpan to their chamber. Tirek is last seen on the balcony where he swears that one day he will overthrow his father and finish what Sendak couldn't: Rule over Equestria.
Since then, Tirek has used magic to compensate for the fact that deep down, he will never be enough to please King Vorak, as explained in The Ending of the End Part 2. It is unclear if Tirek has indeed overthrown his parents or if he just simply left them alongside his brother to conquer Equestria. The fact that Scorpan, who clearly loved them, was still on good terms with Tirek by the time they left their land to travel to Equestria, suggests the latter.
A thousand years prior to the series, Tirek and his brother Scorpan traveled to Equestria so that Tirek could finally fulfill his dream of taking all the magic from the land and becoming all-powerful; but when Scorpan came to appreciate Equestria and became friends with Starswirl the Bearded, he tried to turn Tirek away from his quest. Tirek refused, and Scorpan warned Celestia and Luna of his brother's ambitions, and, because of this, they were able to imprison Tirek in Tartarus for his crimes while Scorpan returned to his homeland. Before leaving to return home, Scorpan gave Tirek his amulet as a memento of their former bond.
Twilight's KingdomIn "Twilight's Kingdom", it is revealed that when Cerberus left his post at the gates of Tartarus (in "It's About Time"), Tirek was able to escape. After spending his time free recovering his strength, he had eventually regained enough power to absorb a unicorn's magic. Celestia received a vision of this event and, after meeting with Luna, Cadence and Twilight to asses the threat of his return, sent Discord after Tirek, as he could sense magical imbalances and therefore make it easy for him to find Tirek. Discord, using the guise of a unicorn, discovered Tirek in alleyway and confronts him. Tirek initially commends Discord for his "escape" from his imprisonment, only for Discord to bind him with shackles, revealing that he had switched alignments and is reimprisoning Tirek for his friends. Taking advantage of this new revelation, Tirek convinced Discord that his friendship was a new form of prison and that, if they worked together, he could get the one this friendship could never give him; freedom. Discord, despite his friendship with Fluttershy, agrees. With Discord now at his side, Tirek began devouring the energy and magic from unicorns, pegasi and earth ponies alike from all across Equestria, regaining almost all of his strength.
Knowing that he would seek alicorn magic next, Princesses Celestia, Luna and Cadence, with no options left, called upon Twilight and entrusted all of their magic to her, as Tirek was not aware of the existence of a fourth Princess. As expected, Tirek and Discord assaulted Canterlot in search of the Princesses' magic, only to find the three Princesses without it. Still assured of his victory, Tirek ironically banished the three Princesses to Tartarus and approached Discord, who was comically altering Celestia's stained glass windows. As a sign of gratitude for his efforts, Tirek gave Discord a medallion that he received from "somebody close to him", before seeing the window depicting Twilight and demanding to know why Discord didn't tell him about the fourth Princess. Discord stated that he wasn't sure if Tirek could be fully trusted, but now knowing that he is, tells him about Twilight and her friends. Tirek, though upset over his friend lying to him, does appear to forgive him. Tirek and Discord then headed to Ponyville and captured Twilight's best friends, Tirek draining their power before doing the same to Discord, telling him that he has outlived his usefulness, revealing that his medallion actually came from Scorpan, and that Discord is as worthless to him as his brother was.
Growing to tremendous size from the magic he absorbed with his power even surpassing that of Discord, Tirek sought out Twilight, obliterating her home of the Golden Oak Library in his search, enraging her and driving them to fight in an epic battle. The two were evenly matched, though Twilight seemed to have a slight advantage, and so Tirek revealed the other Mane 5, Spike, and Discord, imprisoned inside orbs. Tirek told Twilight to give him all the alicorn magic in Equestria in exchange for her friend's release, and she agreed, and Tirek released all except Discord, who Twilight then wanted to be released as well. Although not understanding why Twilight would want Discord after he betrayed her, Tirek complies and drained her of all the alicorn magic, increasing his size and strength to titanic proportions. To thank her for her kindness, Discord gave Twilight Scorpan's medallion, this time out of legitimate gratitude, making it the final key to the Tree of Harmony box.
Unlocking the box, the Mane 6 receive Rainbow Power, and confront Tirek with their new abilities. Tirek fires at them with a massive magical blast, only to be confused when his attack has no effect on them. A distressed Tirek asks how it is possible for the Ponies to be undamaged without magic, and Twilight responds by telling him that she possesses the most powerful magic of all; friendship. The Mane 6 then attack Tirek, draining him of his stolen magic and reimprisoning him in Tartarus, undoing all of his actions.
The Cutie Map
In "The Cutie Map", Tirek is mentioned by Rainbow Dash when she reminds Twilight that they along with the rest of the Mane Six, have opened all six keys of friendship, defeated Tirek and received a castle of their own.
Crusaders of the Lost Mark
In "Crusaders of the Lost Mark", Tirek was mentioned again by Pipsqueak, who stated that his battle with Twilight was the cause of the poor conditioning of the schoolyard.
The Cutie Re-Mark
In "The Cutie Re-Mark", in the fourth alternate timeline created by Starlight Glimmer, without the Mane 6 to stop him, Tirek succeeds in draining all the magic in Equestria and is briefly seen causing destruction.
In "Shadow Play", Pinkie Pie mentions Tirek while recounting the threats Equestria has faced over the last thousand years to Starswirl the Bearded.
The Mean 6
School RazeTirek reappears in Season 8's two-part finale, "School Raze", in which it's revealed that he is pen pals with Cozy Glow. He also conspired with Cozy for the sake of getting revenge. Cozy Glow was successful in trapping the Mane 6 in Tartarus, during which Tirek told them that Cozy Glow was behind it and his involvement in her plan. However, Twilight reminded him that if they were trapped in Tartarus, he'd be trapped with them for eternity. Pinkie Pie annoyed Tirek to the point of giving Twilight what remained of his magic so the Mane 6 could escape just to get rid of them.
After the Young Six broke Cozy Glow's spell, Tirek got his magic back, which hit him in the head and knocked him down. Later, a bored Cerberus lay next to Tirek with him remarking that it may be boring in Tartarus but at least Cerberus isn't in a cage. When Luna and two Royal Guards imprisoned Cozy Glow in Tartarus, in a cage next to Tirek, Cozy Glow asked Tirek if he wanted to be her friend, much to Tirek's dismay.
The Beginnning of the End
In "The Beginning of the End", while still imprisoned with him, Cozy Glow annoys Tirek by continuing to try and befriend him, before the both of them are suddenly transported out of Tartarus. Emerging within a mysterious cavern, Tirek and Cozy Glow are met by Queen Chrysalis, who immediately accuses them of summoning her, though Cozy Glow assures her that they thought she freed them. As this happens, King Sombra suddenly appears, causing the three to accuse him of summoning them, only for only for Discord (disguised as the ancient tyrant Grogar) to reveal himself to be the one who was responsible for summoning them. Tirek, Chrysalis and Sombra are shocked to see him, as they believed he was only a legend, though "Grogar" assures them that he is real and states that he summoned them as part of his plan to rid Equestria of Twilight Sparkle and her friends.
Seeing that Cozy Glow doesn't know who he is, "Grogar" decides to demonstrate his power by giving Tirek a sample of magic that revives much of his strength. Tirek then tells Cozy Glow that "Grogar" is ancient and extremely powerful, as well as the former ruler of what would become Equestria, claiming that he had heard stories of his tyranny when he was younger. "Grogar" then tells the villains of how he created monsters that roamed the land and took whatever they wanted under his rule, before Chrysalis remarks how he was banished by Gusty the Great, although "Grogar" claims that he was only temporarily weakened when she took his bell; however, Cozy Glow points out that, since he has been weakened before even Tirek was born, he has a very different idea of what "temporarily" means, much to his annoyance. In reality, Gusty the Great really did banish the real Grogar into limbo, from where there is no return.
"Grogar" proceeds to tell the group that he has watched them and their failures to take over Equestria, and asks them why they have always been defeated by the same six ponies each time, Tirek claiming that it is because they are "annoyingly lucky". "Grogar" rebuffs their answers and claims it is because their enemies work together as a team, demanding that the villains join forces with him to take over Equestria. Sombra, however, refuses to serve "Grogar" and arrogantly proclaims that he will take over the Crystal Empire by himself, causing "Grogar" to send him off to the Empire on the conditions that, if he fails, he will serve him or be destroyed again. After this, "Grogar" tells the others to prepare to work together and leaves. Cozy Glow immediately compares working together to making friends, telling Tirek and Chrysalis that they are in luck since she knows "all about that", though the former only flicks her away in annoyance.
Cozy Glow tries to get Tirek and Chrysalis to work together by having them each say nice things to each other, though this falls apart when Chrysalis refuses to say anything nice about ponies. "Grogar" then approaches them and states that he hopes the three of them will be enough to help his plans along, causing Tirek and Chrysalis to ask about Sombra. "Grogar" shows them that Sombra had failed in his plans to conquer Equestria and had again been defeated by the Mane Six, remarking that he will at least serve as an example to them as what will happen if they don't submit to his plans. Having seen this, Tirek, Chrysalis and Cozy Glow unanimously agree to serve "Grogar", though are seemingly left nervous by the thought.
In "Frenemies", as "Grogar" is working, Cozy Glow approaches him and tattles on Tirek for leaving food out, Tirek quickly approaching "Grogar" and telling him not to trust anything she says afterwards; though "Grogar" is quick to point out that he already doesn't trust anything that they say. After being annoyed by Chrysalis, "Grogar" informs the villains that he is leaving and demands that they all stop fighting and find a way to work together so that they can accomplish their goals. Once "Grogar" leaves, Tirek, not listening to his orders, begins to work out by himself (seemingly in an effort to re-obtain his physique from when he had absorbed Equestria's magic). While doing so, he is approached by Cozy Glow, who states that she is organizing a team meeting, which he agrees to go to so long as she leaves him be. At the meeting, Cozy Glow encourages the fact that they all need to trust one another to work together, which Chrysalis finds hard to do as Tirek is trying to steal her magic. Tirek firmly denies doing such a thing (returning the magic he actually had stole to a cupcake that Chrysalis devours), and calls her out for constantly ranting to her log, before joining Chrysalis in telling Cozy Glow that she wasn't left in charge. Cozy Glow then tries to get them all to agree with one another over their common goals, leading them all into singing "Better Way to be Bad" with one another, only for them all to devolve into bickering.
"Grogar" returns at the same time, and, upset to see they have not yet resolved their differences, decides to send them off on a mission to retrieve his Bewitching Bell from Mt. Everhoof so that they can learn to work together. Tirek and the others fight over who should lead the mission based on their previous feats, only for "Grogar" to angrily overpower and remind them that they all failed before and cannot work alone. Upon arriving at the foot of the mountain, all of the villains immediately split off and begin to find their own ways of getting up; Tirek staying behind and making a camp for himself. He proceeds to laugh at Cozy Glow upon seeing her return, and explains to her that he had already deduced that getting up the mountain by himself would be impossible, and so had planned to wait for her and Chrysalis to fail so that he could take what they learned and use it to his advantage. Cozy Glow and Tirek proceed to bicker — Tirek calling her out for her fake cutesy persona and constant manipulations having found out that she was only pretending to befriend him long before they teamed up, and Cozy Glow criticizing his arrogance, while also mocking him for talking to his "Gram Gram" in his sleep — until they are approached by an Ophiotaurus, which they both blame each other for attracting. Suddenly, a female Ophiotaurus arrives and seduces the other one, Tirek quickly realizing that the former is actually Chrysalis in disguise, who admits that she needs their help, causing Tirek to gloat about his own strategy.
That night, Tirek and the others begin to bond with each other over their previous endeavors and hatred towards The Mane Six; him remarking on how he turned Discord against his friends and used their emotions against them, and that Cozy Glow's plan to destroy all magic would have been worthwhile if it meant seeing Twilight and her friends defeated, also admitting that working with Chrysalis and her may not be such a bad thing. The next day, the three villains proceed to combine their abilities in order to scale the mountain, only to find that the cave at the top is protected by a magical barrier, which Tirek cannot absorb since he can only take magic from living beings. With some convincing, Chrysalis allows Tirek to take her magic to become powerful enough to create an opening in the barrier, allowing Cozy Glow to enter the cave and retrieve the bell. Tirek then returns Chrysalis' magic, stating that he wasn't sure he would do so and that it seemed smarter to work with her than fight. The villains begin to reflect with one another over how it felt to rely on others for a change, before Chrysalis snaps them out of it, not wanting friendship to infect her like it did her hive. Reailzing that they almost reformed, the three vow to remain focused.
The three then concur that "Grogar" has grown too powerful and decide to betray him together, and Tirek agrees that they can all go back to trying to destroy one another afterwards. He and the others later return to "Grogar's" lair and fool him into thinking that they failed while yet still becoming allies to his delight, though in reality have kept the bell for themselves.
A Trivial Pursuit
In "A Trivial Pursuit", Tirek is mentioned by Twilight and Mudbriar with him and Scorpan being the answer of who came to steal magic from Equestria.
The Summer Sun SetbackIn The Summer Sun Setback, Cozy Glow sees "Grogar" leaving and asks where he is going. He reveals that since his minions "failed" to recover the Bewitching Bell for him, they will need another source of power to defeat Twilight and her friends. After "Grogar" leaves, Cozy Glow informs Chrysalis and Tirek that he is gone. The villains voice that they don't trust "Grogar" and try to figure out how to use his bell like ringing it but nothing happens. Cozy Glow then points out that Twilight mentioned that the Archives in Canterlot has a restricted area and the villains set off on their "road trip".
The three villains hide in Canterlot and only Chrysalis and Tirek notice so many ponies out in the night. Cozy Glow reveals that it's the Summer Sun Celebration with Chrysalis asking how many holidays these ponies have. She believes that it will be easy to get in until Tirek points out that Canterlot has increased security. After Chrysalis fails to enter through the main doors, she returns to her allies and informs that it will be more challenging. The villains then overhear Twilight's friends and Discord talking about their responsibilities for the holiday. Tirek believes it to be impossible since the security is increased with Twilight's friends "bumbling about". However, Chrysalis sees it as an advantage to use as a distraction since they heard everything and gives instructions to Tirek and Cozy Glow.While Chrysalis and Cozy Glow secretly sabotage the unicorns and Pegasi, Tirek secretly sabotages the Earth ponies of Appleloosa who are prepare the catering by hiding in the bushes and discreetly absorbing the Earth ponies magic which turns him back into his third form. This causes Braeburn to assume that the food is contaminated, causing the rest of the Earth ponies to panic. Tirek laughs at this while stealing some food on the way. The villains watch all the panic and chaos unfold before deciding to incapacitate the security. Cozy Glow distracts a guard while Tirek steals his magic and Chrysalis uses his star badge to the main doors for them to enter.
They search for the archives which also wakes up a security goose which follows them. However, Chrysalis disguises herself as another security goose to get it to leave and the villains finally find and break into the Archives. They search through the Archives until Cozy Glow finds a book about how to use the Bewitching Bell and uses another book to break it out of it's chains.This gives the villains time to leave Canterlot back to "Grogar's" lair while Twilight and her friends are able to fix the holiday. "Grogar" also returns tells his cohorts that he has found success where they all find "failure". He reveals that he located what he wanted and will retrieve it the next day before they begin his plan to take over Equestria. Tirek is still sulking that he had to give the magic of the Earth ponies back to them, in which Chrysalis and Cozy Glow tell him to stop doing and remind him that "Grogar" would become suspicious if he found out about their "road trip" in which Tirek claims that he doesn't have to like it. Cozy Glow reveals that she didn't like it when the Mane Six managed to fix the holiday, until Chrysalis reveals that the goal was not to destroy but to distract in order to get the book. Tirek reminds them that they can't waste any more time because they must master the bell before "Grogar" returns. Chrysalis reveals that they managed to stay ahead of everyone so far until Cozy Glow remarks how easy it was to turn the Earth ponies, unicorns and Pegasi against each other, in which Chrysalis decides would be something to think about.
The Ending of the EndTirek, Chrysalis, and Cozy Glow absorb "Grogar's" magic from his bell, turning Tirek back into his third form but much stronger. They then drain "Grogar's" current magic, revealing him to be Discord. When Chrysalis intends to take Discord's magic, Tirek says only Discord can control it. They agree to let Cozy Glow test this knowing that she can't go through with betraying them and take the magic back at her request when she can't control it, before setting out to conquer Equestria. Tirek drains the Pillars of Equestria and imprisons them in the caves beneath Canterlot with Starlight Glimmer, who was captured by Chrysalis, before both go to Canterlot to fight alongside Cozy Glow, during which they destroy half of Canterlot and almost kill Twilight twice, with Rarity stopping them the first time, and the other Mane 5, Spike, Celestia, Luna, and Discord holding their magic beam back the second time so Twilight can escape, and are eventually overpowered and imprisoned by the villains.
In Part 2, where Cozy Glow wants to kill the prisoners and Chrysalis wants to torture them, Tirek instead wants to hunt down Twilight as he knows that she is the biggest threat. They argue over Cozy Glow trying to take Celestia and Luna's magic from the bell, Tirek saying they must figure out Discord's magic first. Discord pretends to offer to tell them in exchange for the safety of the others, and insults Tirek into trying to blast him, which Discord reflects to release Starlight from her imprisonment, allowing her to release the others, and while the other Mane 5 and Spike run off to get Twilight, Starlight, Celestia, Luna, and Discord fight Tirek, Chrysalis, and Cozy Glow, who reimprison them.When the Windigos return from the villains turning ponies against each other, Tirek says they are ancient magic and should be destroyed. Afterwards, the Mane 6 and Spike arrive. During an attempt to get the bell, Tirek chases after Twilight, who is trying to distract him, after which Tirek foils Applejack's attempt to get the bell. When Chrysalis threatens Spike, the villains nearly destroy the Mane 6, but many unicorns protect them and most of the ponies' allies enter the battle.
In the end, the Mane 6, Spike, the Young Six, and the Pillars unleash a rainbow which destroys the Windigos and takes away Grogar's power from Tirek, Chrysalis, and Cozy Glow, turning Tirek skinny and frail again. After Pinkie drops a giant cupcake on them with Discord's magic, which, along with Celestia and Luna's magic, is returned, Celestia, Luna, and Discord turn Tirek, Chrysalis, and Cozy Glow to stone as punishment for their crimes after Celestia and Luna ponder over what they should do given the scope of their crimes.