I'm thinking on the Rmoahls here. According some mages they were a previous human race whose last survivors can be found currently in Astral (as blue giants) and who have some magical proficiency.

What if the Rmoahls were the Neanderthal mages? They could be the Bound-mages, while the Sapiens could be the Awakened ones. They don't need to be blue giants, tgat could be a secondary Astral effect. Eventually, seeing their species are doomed against the sapiens, the rmoahls would exile themselves to the Astral, as the last remnaints of their doomed species.