The two-part season finale deals with a new threat named Lord Tirek, who wants to rule Equestria by absorbing all magic, as well as Twilight Sparkle trying to learn what she should do with her new role as a princess.

"Twilight's Kingdom" was directed by Jayson Thiessen, co-directed by Jim Miller, produced by Sarah Wall and Devon Cody, and written by Meghan McCarthy.

Storyboarding the episodes' battle scene was also difficult as the crew needed to correctly focus on the timing, gravity, and movement.

Celestia has a vision revealing that an evil centaur named Lord Tirek has escaped from Tartarus and is now draining ponies of their magic.

Twilight returns home to Ponyville, disappointed at being unable to help, and heads to the castle ruins with her friends in the Everfree Forest to catch up on studying.

Discord interrupts them, teases them about his mission, and reminds them of the locked chest at the base of the Tree of Harmony (from "Princess Twilight Sparkle").

Twilight realizes Discord mentioned their shared journal, and finds stories written by the other five where they were challenged in regard to their core Element of Harmony, and were able to help another, receiving an item in return.

Twilight is summoned back to Canterlot, where Celestia reveals Discord's treachery, and that Tirek now has his sights set on taking the princesses' magic for himself.

The main villain in "Twilight's Kingdom" is Lord Tirek; he is based on a centaur, with the head, arms, and chest of a human; and legs, hindquarters, and tail of a horse.

However, they changed the color of his upper body to black, which made Tirek appear less intense and the more expressive parts of his body—the face and arms—more prominent.

[2] According to Timothy Packford of DHX Media, storyboarding action scenes, such as the one in "Twilight's Kingdom", was difficult since the stories' important points might be lost.

An Entertainment Weekly writer graded them an A−, describing the two as carrying "a Frozen-y empowering theme (and a sly Godfather reference)".

[9][10] Writing for TheWrap, Johnnie Jungleguts listed the two-parter as the best episode of the My Little Pony franchise due to its entwined plot lines and lore.