The Troupe, is simply a small group of like minded Arrancar, all of whom have no real home. They will often meet in either Hueco Mundo or the Human World to work together on various goals each individual may have, or simply to just socialize. They also help each other to fight off Shinigami, Quincy and Fullbringers on the hunt, and inversely, to hunt their own prey. There’s no leader or structure, it’s just a group of people with similar goals working together when it suits.
It's often referred to as the troupe, as the founding members still see it as a performing circus that travels the human world, bringing their own twisted form of entertainment to the masses. This is often a mix of torture and murder, sprinkled with a veil of 'magic performances' or 'music'. Not all members of the Troupe take part in this or believe in the view that they're putting on a performance, but it's something many do enjoy.
Each member has a number tattooed somewhere on their body (similar to the Arrancar of Las Noches), to show the order in which they joined the Troupe. When performing, each will wear a mask of sorts to hide their faces. For now, the fortress of Las Noches is their current hideout though most of them will not be there all at once.
The Troupe has a rather simple beginning. Levialle and Isabella were 'performers' for a while together, running throughout the human world having fun. After one of their largest performances, Levialle suggested they start a circus of friends to make their performances even more grand. Isabella excitedly agreed, and they went about recruiting like minded Arrancar into their fold. The rule of recruitment being that in order to join the Troupe, you must be completely different than the other members but exactly like them. There's a "No Clones" policy and Levialle is the one who does all of the recruiting.
Years on, there are about half a dozen members of the Troupe, all of whom meet from time in the sands of Hueco Mundo. At this point, they hadn't taken any measures to earn themselves notoriety with other spiritual beings.
*In order of joining