Vrak Nashar
Character
As one would expect from a society built upon the remnants of Purebloods, the Resurgent Empire carries a heavy caste system. This caste system is based upon the segmentation of ranks, allowing certain members of society to work together more closely while separating others.
Everyone within the resurgent Empire, whether Pureblood or not, is part of one of the three Castes.
One chooses their own Caste upon joining the ranks of the Empire. It does not matter whether you can use the force or not, everyone has a caste and it is what and who they work with.
The benefit of the castes is a simple one, once inside the fold of one of the three a person has access to more resources that fit them. A Massassi will be surrounded by soldiers, a Kissai will more freely walk among the libraries, and a Zugurk would see their opportunities unfold. The Castes offer opportunity, a way to rise through the ranks of the Empire in a position that is suited to the individual.
Being part of a particular Caste does not make it impossible to attain certain positions, it simply makes it easier. For instance a Massassi is much more likely to become an Admiral than a Kissai, similarly a Zugurk is much more likely to be a Planetary Governor than a Massassi. The Castes are a way to make ones chosen path easier, though they are by no means a constraint on ambition. With enough force of will, anyone of any caste could do anything, though they would be met with resistance from the other caste's.
The Castes are important. They ensure that the Empire works together, mostly because to get anything done at all you require members of all Castes working together and sharing their information. They are a balance on one another. The armies of the Massassi would get nowhere without the support of the Kissai, the Kissai's research would stall without the support of the Zugurk, and both would fall without the protection of the Massassi. Each Caste is a balance on the other.
Once a Caste is chosen, an individual generally swears their loyalty to one Sphere of Influence of the Council. It does not matter which Caste one is a part of, though certain Caste's are more likely to swear loyalty to certain Spheres. Of course this loyalty is based on the words of Sith, and thus really only nominal in nature.