In the Lord of the Rings , however , elves were described as human sized ( and if anything taller ) , hence changing the description of elves . This prompts Grimm to assume a tripartite division of light elves , dark elves and black elves , of which only the latter are identical with dwarves , while the dark elves are an intermediate class , `` not so much downright black , as dim , dingy '' . In support of such an intermediate class between light elves , or `` elves proper '' , on one hand , and black elves or dwarves on the other , Grimm adduces the evidence of the Scottish brownies and other traditions of dwarves wearing gray or brown clothing .