In the Equine Zone, there are two planets. One of them was Equestria, which everyone knows. But there is another planet next to it, named Ponyland. Ponyland is a planet that you can get to on the other side of the rainbow. But, since it is physically impossible to travel on a rainbow, you could also get there via TARDIS. The biggest planet of the Equine Zone is Equestria, home to the Canterlot princesses. If they were to fall, it could mean the death of ponies all over the universe…

A long time ago, there was a centaur named Tirek. On Ponyland, he attempted to use the Rainbow of Darkness to bring everlasting night so that he could ride his Chariot of Midnight. However, he was defeated.

Later on, Tirek was resurrected by the Daleks, believing that if Tirek could steal light and magic, he could exterminate planets just by absorbing the energies of the native people. They left him in Equestria so that he could fulfil his mission.

Tirek briefly went back to Ponyland and forced his servant, Scorpan, to serve him again, calling him his "brother". He went to Equestria, with a mission to steal Equestrian magic, as ordered by the Daleks.

However, Tirek's brainwashing of Scorpan was weaker than when he brainwashed him on Ponyland (and took his kingdom). He grew to appreciate the ways of Equestria and even befriended a young unicorn wizard (Star Swirl the Bearded). Scorpan pleaded with his "brother" to abandon their plans, but Tirek refused.

Scorpan then informed Princess Celestia and Luna of Tirek's intentions. Scorpan returned to his human prince form and returned to his homeland, while Tirek was imprisoned in Tartarus for many centuries.

Now, you do know that Tirek escaped Tartarus because Cerberus left his post. However, you don't know the REAL story…

Tirek lies in his prison, bored. Suddenly, out of nowhere, a woman appeared inside his cell. She had short hair, red lipstick and an eyepatch that was actually an Eye Drive.

Madame Kovarian broke the ice. "Hello. What's your name?" Tirek didn't respond. "Oh, I know all about you. I heard that you tried to steal the magic from this land. But, oh, look at you. You used to be giant, but now, you're just a weak pony, a useless, abandoned Dalek pawn." Tirek suddenly looked at Kovarian. "That's right. I know how you got resurrected. I can start you on your mission again. You won't be working for the Daleks anymore, but you'll be working for me."

Tirek was interested to hear Kovarian's proposal. She presented a picture to Tirek. "This man is the Doctor. This man defeated me many times. I tried to have him killed at Lake Silencio. One of my agents, Chrysalis, managed to lure the Doctor here, but that bastard ruined everything! He slaughtered the Changelings with his own hands. Another pony, King Sombra. He worked for the Daleks so that he could help them rebuild their ships. Sure, the Doctor wasn't their target, but with the power they had, they could have killed him in one fell swoop!"

"This is your mission, Tirek. Rampage all over Equestria and steal the ponies' magic. You should be able to get Princess Celestia's attention and hopefully, she will call the Doctor for help. Then, what you will do, is kill him. I don't care what you do, just make sure he doesn't get out of Equestria alive. So, do we have a deal? I can finally have the Doctor killed so that he can never answer the question, while you can take revenge for your brother's betrayal. How about it? Oh, I know about that too."

Tirek thought about it for a moment, then said to Kovarian, "I accept your deal."

Kovarian smiled and snapped her fingers. Suddenly, three Silents appear outside the gates. They shock Cerberus with electricity in order to distract him. The Silents reappear all over Tartarus, shocking him and disappearing to make them forget their appearance. Eventually, Cerberus is chased out of Tartarus.

Madame Kovarian cuts open the bars on his cell and lets Tirek out. While he leaves, Kovarian tells him, "Do not disappoint me."