Prince Rutherford

Prince Rutherford is a male yak and the prince of the kingdom of Yakyakistan. He first appears in the season five episode Party Pooped.

Season five
Prince Rutherford appears in Party Pooped as part of a Yakyakistani delegation to Equestria. When he first meets Princess Twilight Sparkle, he expresses a desire to foster a good friendship between ponies and yaks. However, over the course of their visit to Ponyville, Rutherford and his entourage trample and destroy everything with which they take even the slightest issue.

Twilight serves Rutherford a banquet of traditional yak foods, but Rutherford destroys the banquet table because he doesn't like how the food tastes. Applejack makes him and his fellow yaks Yakyakistan-style hay beds, but Rutherford destroys them because they aren't made from Yakyakistan hay.

The yak prince reacts similarly to Fluttershy's animal friends, Rarity's fabrics at Carousel Boutique, Rainbow Dash's snow, Mrs. Cake's baking, and Spike's piano playing. Eventually, Prince Rutherford becomes so frustrated that he decides to leave Ponyville and declare war on Equestria.

Thanks to Pinkie Pie—who travels across Equestria in an attempt to help the delegation—a friendship party in Ponyville boosts Rutherford and the yaks' spirits. When Pinkie approaches Rutherford and talks at length about what makes Equestria great, Rutherford calls off his declaration of war and becomes good friends with the ponies.

Season seven
In Not Asking for Trouble, an avalanche falls in Yakyakistan while Pinkie Pie visits them. Pinkie suggests to bring over her friends to help, but Prince Rutherford and the other yaks refuse.

IDW comics
Of, Prince Rutherford appears on page 20, angry that the Griffonstone Boffyball team scored a single point on the Yakyakistan team. In, he appears as a participant in trade negotiations between Yakyakistan and the Crystal Empire. During the negotiations, Rutherford becomes good friends with Prince Blueblood. In the mini-comic For the Pony Who Has Everything, Rutherford appears in attendance of Princess Celestia's birthday party. In, Rutherford appears on page 4. He also appears in, in which dragons threaten Yakyakistan.

Personality
Prince Rutherford is portrayed as loud and incredibly short-tempered. He is usually gracious enough to meet with Princess Twilight and her friends on calm footing, but he becomes volatile if something displeases him, typically flying into a destructive rampage. He is, however, cultured enough to appreciate classical music.

Rutherford speaks in broken sentences, omitting most grammatical articles from his speech and sometimes referring to himself and his entourage in the third person.

Quotes
"Me honored. Yaks hope for great friendship between ponies and yaks. [echoing] Friends for a thousand moons!"

- Party Pooped

"If things not perfect, yaks get mad. Yaks always get mad when things not perfect!"

- Party Pooped

"Not perfect! Yaks destroy!"

- Party Pooped

"Yaks smash!"

- Party Pooped and

"Music beautiful. Much soul."

- Party Pooped

"We leave now! Yak go to train, return with more yaks! We declare war!"

- Party Pooped

"Pink pony work hard to make yaks feel at home. Now yaks happy. No declare war."

- Party Pooped

"Pink pony, you understand yaks now."

- Party Pooped

"Griffon team scored a point...? But... yaks wanted total victory... Yak win... not perfect!"

"Blueblood right. Rutherford need to take more time to himself."

"Yaks glad Celestia not let us go to war with griffons. Yaks like griffons."