Castle of Friendship

The Friendship Rainbow Kingdom is a kingdom that is gained by Princess Twilight Sparkle in My Little Pony Friendship is Magic  season four.

Development
"QUEST FOR A KINGDOM".

History
Princess Twilight Sparkle's potential future kingdom is discussed throughout My Little Pony: Twilight Sparkle and the Crystal Heart Spell, is later discussed briefly at the beginning(s) of My Little Pony Equestria Girls/My Little Pony: Equestria Girls: Through the Mirror, and is again discussed briefly on page 13 of the story Reflections Part 1.

Season four's two-part finale is named "Twilight's Kingdom" after the Friendship Rainbow Kingdom. In the second of the two episodes, Twilight's Kingdom - Part 2, "Princess Twilight Sparkle is awarded her very own castle (which is built via magic").

Twilight's Kingdom - Part 2
At the climax of the episode, the crystalline tree-palace is created from the mysterious chest that sprouted at the base of the Tree of Harmony in Princess Twilight - Part 2. The chest is launched from the tree to a site on one side of Ponyville where, in a matter of seconds, the tree grows into its full size.

The tree-palace bears some resemblance to the destroyed Golden Oak Library but is many times larger and appears to have a multi-level palace in its branches. The structure has at least one banner flying on the side marked with Twilight Sparkle's cutie mark.

Inside the main entryway can be seen a staircase running up inside the trunk. Apart from a column-lined corridor, the only room inside the palace as yet seen is the throne room where the Mane Six and Spike each have a throne around a central star-shaped dais.

Merchandise
"MY LITTLE PONY fans can discover the newest royal empire inside the FRIENDSHIP RAINBOW KINGDOM castle playset, a grand three-level palace fit for a pony princess! Use the friendship keys to unlock a number of magical accessories within the kingdom, including a wardrobe, vanity, book, and treasure chest. Pony friends can travel the kingdom in style on the rolling cloud car, taking a ride down a fun swirly slide. Stops along the way include a lookout tower, golden balcony, swing, and more. Includes PRINCESS TWILIGHT SPARKLE figure, key, cloud car, and themed accessories. (Ages 3 years & up/Approx. Retail Price: $39.99/Available: Fall 14)". It includes depiction of Spike. The playset's packaging, displayed along with it by Hasbro at the 2014 American International Toy Fair, lists its name "FRIENDSHIP RAINBOW KINGDOM" with a trademark symbol. Some promotional photos are of a different version of the playset, in which the first floor's interiors are instead images of the same designs as in Canterlot Castle and the design of the second floor's interior is instead the same as of Golden Oak Library's first floor.

A Keys Of Friendship DVD cover depicts Princess Twilight Sparkle with the Friendship Rainbow Kingdom in the background.