Planars: Natives of the Outer and Inner Planes – whether they're human, humanoid, or another shape altogether. Unlike primes, Planars can see portals to other planes. Planars are considered extraplanar everywhere except his home plane, and can be summoned without warning by abilities designed to grab planar creatures and haul them to the caster's location.
Primes: The [often unfairly tagged] Clueless, are simply natives of the Prime Material Plane. While they're often considered know-nothing leatherheads and easy marks for peelers, primes do have one big advantage over planars: They're not subject to any spells that effect extraplanar creatures, no matter where they go.
Petitioners: The spirits of deceased primes and planars who inhabit the plane of their deity or alignment. Petitioners take many shapes but are usually indistinguishable from other folks, at least at first. They don't remember their former lives and only vaguely reflect their previous personalities; they're shaped into whatever form their power or their alignment requires. About the only thing they have to work toward is the hope of attaining union with their power or plane. They never leave their home planes for fear of permanent dissolution.
Proxies: The hand-picked servitors of the powers (sometimes called gods). As servants of their deities, proxies act in their powers interests and according to their wishes. Some proxies retain their original forms, while others are reshaped into forms favored by the powers. Naturally, their personalities and intentions vary, depending on the particular powers they serve. Regardless, it's a sre thing that proxies answer to their gods and only to their gods, and a basher had better treat'em with the respect they're due. Not all berks have a direct pipeline to their deities, after all.
Powers: Whether a body worships them as gods or just thinks of them as really mighty bloods, the Powers are the high-ups of the planes. They rule over certain areas, establishing their dominion and enforcing their whims as their natures demand. They offer spells and abilities to those who worship them. Within their realm, the powers rule supreme; no mortal cutter's ever going to come close to challenging their might.