Ensemble Square (アンサンブルスクエア ansanburu sukuea) is an entertainment company that exists on its own miniature island within Japan. Introduced in EP:Link, Eichi Tenshouin, the agency president, and Ibara Saegusa, his collaborator, intend to use Ensemble Square to revolutionize the idol industry.
It is the parent entertainment company of dozens of talent agencies, which are housed inside the building of Ensemble Square's agencies, Starmaker Production, Rhythm Link, New Dimension, and Cosmic Production contain the main units from Yumenosaki. See the Ensemble Square page for more information.
Main units are the default units every idol is in. These units are the same units that every character was in when attending Yumenosaki.
Shuffle units are comprised of members from multiple units. They exist on a temporary basis, usually until they complete the job they have been assigned.