[Raynor]

I would say we need to consider more the influence of Orome, who seems to have been known to them (Bema); they also seem to be quite acquainted with the mearas, who most likely are related to Nahar. The Rohirrim are also descendants of the Edain, which might have given them even greater perception of the standing of the mearas, at least. They must have become aware, at one level or the other, that near them were beings related to the blessed lands, likely filled with magical powers. Their natural affinity with the larger race of the horses might be a testimony to their affinity with the "Light side".