Magic and Mechanics
Palavers: forces and beings in the world caused by the minor animistic gods merging with reality after being abandoned by the pantheon. Examples: nature, fey, dragons, and the detail distinction in the different arcane schools.
Many of the races are semi-divine in nature, such as the Palavers. Conversely, the Companions (core races) are grounded in their mortality, and consider themselves above the wispy creatures born from the land. So yes, the core races are canonically a different species/tier than the uncommon races. This does not include half-breeds.
While sorcerers do not exist, there are less blatant displays of arcana use throughout the land.