Castle of Friendship

The Castle of Friendship is a castle in Ponyville that Princess Twilight Sparkle acquires in the My Little Pony Friendship is Magic season four episode Twilight's Kingdom - Part 2. It is called the "Castle of Friendship" by Spike in The Cutie Re-Mark - Part 2 and in some merchandise, the Friendship Rainbow Kingdom in other merchandise, and Twilight's Castle in Gameloft's mobile game and other merchandise.

Development
In a September 2013 presentation held by Hasbro Australia, a slideshow was shown depicting upcoming My Little Pony and Equestria Girls merchandise. One of the slides in the slideshow relating to Rainbow Power contains the text "QUEST FOR A KINGDOM".

Twilight's new home was designed by background designer Phil Caesar in conjunction with art director Ridd Sorensen and BG painter Geoff Manson. In May 2014, Jim Miller was asked regarding Twilight's new home "Any rooms we are yet to see? :) Involving a certain familiar-looking wooden library maybe?" and answered "You'll have to wait to find out!" Later in the same month, Miller was asked "So is there an official name for Twilight's new crystal-tree-house castle-thing?" and answered "You'll have to wait till season 5 to find out!" In late November 2015, Miller confirmed the castle's name.

Season four
At the climax of the episode Twilight's Kingdom - Part 2, the crystalline tree-castle is created from the mysterious chest that sprouted at the base of the Tree of Harmony in Princess Twilight Sparkle - 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-castle bears some resemblance to the Golden Oak Library, at least the aboveground portion of which is destroyed earlier in the episode by Lord Tirek, but is many times larger and appears to have a multi-level castle in its branches, which includes a great balcony, two spires, and a tower. The structure has at least one banner flying on the side marked with Twilight Sparkle's cutie mark, and the top bears a large crystal star. Two sets of five strings of beads hang off the side of the structure much like the white beads that hang off the Tree of Harmony. At the foot is a great golden stair for the two-leaved golden door into the tree's body. Two open lancet windows flank the door.

The lobby's two stairs lead into the castle rooms where lancet two-toned green glass windows and crystalline lathed columns with scrolled tops line the hall decked by a brown rug with scrollwork. At its end is a golden-framed green glass fanlighted door to the throne room where the Mane Six and Spike each have a crystalline throne about a star-shaped dais on a golden dish on a violet rug with scrollwork. Even with its door are a set of green glass spire lights.

Season five
Beginning with the season premiere, the castle takes the Golden Oak Library's place in the theme song.

In The Cutie Map - Part 1, the castle reacts to the Mane Six's cutie marks, and a crystal platform rises from the center of the throne room and creates a three-dimensional interactive map of Equestria. The map calls the Mane Six to a remote village to solve a friendship problem.

In Castle Sweet Castle, the castle is shown to contain high-rising ceilings, long hallways, and a dining hall that Twilight and her friends hold a pancake breakfast in. To make the castle feel more like a home to Twilight, her friends fashion a gem-lined chandelier from the Golden Oak Library's roots and hang it in the throne room. In addition, Rarity decorates the dining hall, Applejack spruces up the kitchen with "rustic farm decor," Rainbow Dash puts up Daring Do posters in the library, Fluttershy places some stuffed animals in Twilight's bedroom, and Pinkie Pie installs a number of hidden confetti cannons.

In Tanks for the Memories and Make New Friends but Keep Discord, Spike has his own bedroom in the castle. In The Lost Treasure of Griffonstone, the cutie map calls Pinkie Pie and Rainbow Dash to Griffonstone.

In Do Princesses Dream of Magic Sheep?, Twilight's bedroom is first seen.

The library in Twilight's castle makes its in-series debut in Made in Manehattan.

In Hearthbreakers, the castle is decked out for Hearth's Warming Eve.

In Scare Master, a dangling sign with a crown on it hangs outside, most likely to play up the horror movie cliché of a haunted castle.

In The Cutie Re-Mark - Part 1 and The Cutie Re-Mark - Part 2, each time Starlight Glimmer and Twilight alter the timeline, the castle disappears, but the Cutie Map remains due to its connection to the Tree of Harmony.

Depiction in Rainbow Rocks
Twilight Sparkle and her friends are seen in this castle in My Little Pony Equestria Girls: Rainbow Rocks, gathering books for the castle's library, when suddenly Twilight notices a book vibrating. The book has Princess Celestia's cutie mark on the cover. She opens it and finds out that her friends from Canterlot High School are in trouble. Through research, she discovers that three sirens were banished to the human world by Star Swirl the Bearded. She makes some adjustments to the Crystal Mirror from the first film to make it able to open at any time, as opposed to every thirty moons.

Chapter books
The castle appears in the My Little Pony Equestria Girls: Rainbow Rocks film screenplay novelization My Little Pony: Equestria Girls: Rainbow Rocks: The Mane Event.

IDW comics
The castle is shown in, in , in My Little Pony: Equestria Girls Holiday Special, in , on 's Hot Topic cover, in , and on 's Hot Topic cover.

Commercials
The castle is seen during the Mane Six's brief cameo in the NFL's Together We Make Football commercial during Super Bowl XLIX.

My Little Pony (mobile game)
The castle is featured in Gameloft's mobile game under the name "Twilight's Castle".

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 2015 variant of the castle, called the Princess Twilight Sparkle's Kingdom playset, comes with a POP figurine of Princess Twilight Sparkle.

In Mary Jane Begin's My Little Pony: The Art of Equestria, the castle is featured on pages 6 as "Twilight's Castle" and 52 as "Castle of Friendship". It is also called "Castle of Friendship" on page 9 of Matthew Reinhart's My Little Pony: The Castles of Equestria pop-up book.

A Keys Of Friendship DVD cover depicts Princess Twilight Sparkle with the Castle of Friendship in the background.