It's hard to communicate just how much bigger than humans these guys are when they're set against a plain background: in-game, they tend to stand maybe 8-9 feet tall, albeit with a hunch. I wonder if that was always the intention, because then they must also be able to find giant wolves for their wolf-head hoods. Did you see them as more or less human-sized?
I'm not entirely sure if they were mentioned in the original trilogy, but we are also working with information based on the LOTR pen-and-paper RPG that is like 20 years old, so it is possible it is a reference from there, which could have been entirely made up or taken from the silmarils/Grey Havens etc. (which we DON'T have the rights to directly work from).