Nintendo has a bunch of internal teams, and few of them are named. One of those that does have a public profile is Monolith Soft, a studio best known for developing the much-loved Xenoblade series. Now, though, they're helping out with the development of The Legend of Zelda: Breath of the Wild.
Shigeru Miyamoto announced the collaboration to Game Informer saying: "Yes they [Monolith Soft] are involved in this Zelda. People from Tokyo and Kyoto are working together on this. There is a team of over 100 helping work on this project, and their work has really been helpful."
Of course, this is isn't the first time Monolith Soft has helped other internal teams at Nintendo on a Zelda game, the first time being on The Legend of Zelda: Skyward Sword for the Wii.