In Tolkien's The Fellowship of the Ring
, the type of demon
that Gandalf battled in the Mines of Moria
. As morgandorf
notes below, the balrogs were Maiar
corrupted by Melkor
. The passage cited seems to indicate that not all Melkor's Maiar flunkies became balrogs, only those whose nature was imbued with fire (whether by Melkor or Eru
is not clear). The word "balrog" is Sindarin
, rooted in Quenya
"valarauko" or "malarauko" ("demon of power"). Compare Latin "val-", as in "valence
" and "valor
In fantasy RPG, drawing heavily on Tolkien for many of the creatures, I have heard of balrog interpretations for at least 5 systems: Dungeons and Dragons, RuneQuest, MERP, Palladium Fantasy, and a Middle-Earth scenario for Sid Meier's Civilization II. In D&D "balrog" is usually synonymous with "Type VI demon".
See also Balrog Award.