User blog comment:Ralok/Destiny Wishlist/@comment-70.208.195.106-20140919195022/@comment-160529-20140925233549

Grimoire Card - Psion: Psions are smaller than all other Cabal morphs, and may be an unrelated species. Hyper-intelligent, fast and unpredictable, they possess strong psionic capabilities - including the ability to emit disorienting and deadly psychokinetic Arc blasts.

Its pretty heavily implied that the Cabal is a faction composed of at least two species, the ickle psions, and the big pacyderms which I just call cabal since they seem to be the leaders.