Two characters named Gothmog are mentioned in
Tolkien's writings. One is the Balrog of the Silmarillion, kept
from the earlier version found in Book of Lost Tales. The other
is probably named for the Balrog and is the Lieutenant of Minas Morgul
in the Third Age, spoken of in the Return of the King.
In BoLT, Gothmog was the son of Melko
(Melkor/Morgoth).
In later versions, none of the Valar had children, so this concept was
dropped.
But in BoLT,
this gave him special status as all of those people opposed to the
Valar
of Valinor were under Melkor. His mother was called Ulbandi, in one
spot,
and the ogress Fluithin in another. Gothmog was also called Kosomot. As
the
book goes on, we find that Kosomot is Gothmog, Lord of the Balrogs. In
BoLT's
name list for the Fall of Gondolin, Gothmog means "Strife-and-hatred"
with
mog
as "detest/hate" in the Gnomish (Noldorin) dictionary, and he's called
"Captain
of Balrogs". A later name list in the 1930's shows goth as
meaning "Lord" or "Master". In Eldarissa
(Eldar language distinct from Noldorissa), Gothmog is known as Kosmoko
and
Kosomok(o)
In BoLT2, he is prominent in "The Fall of
Gondolin".
It speaks of him as "lord of balrogs, captain of the hosts of Melko".
In
another, BoLT1's "The Coming of the Valar", he is called a "marshall "
of
the hosts of Melko.
At the Fall of Gondolin, Gothmog had the metal
dragons
(robots) of Morgoth pile themselves at the northern gate of Gondolin
and
knock it down. The top metal beasts "opened about their middles, and an
innumerable
host of the Orcs, the goblins of hatred, poured therefrom into the
breach...".
(In later stories, dragons are organic, not metal.) Later, when the
elf,
Rog, and his people called "The Hammer of Wrath", attacked and killed
balrogs,
Gothmog stepped in again. He had a group of his demons attack from the
front,
then fall back to lure them between two much larger flanking forces.
The
elves were supposed to try to pull back, but instead attacked more
fiercely
forcing onward and destroying those who lured them, then killed many
bands
of the besiegers, until they were at last overpowered by numbers of
Orcs
and Balrogs and by a firedrake. The loss of Rog's force hurt the morale
of
the elves, gave Melko's forces the gate, much of the walls, and a good
part
down to the center of the city. A firedrake and Gothmog together beat
down
Tuor who had saved Ecthelion, so Ecthelion rose up and attacked
Gothmog,
driving the spike of his helmet into Gothmog's chest and toppled him
over
into the king's fountain so that they fell together and their weight
took
them deep and drowned them.
The "Fall of Gondolin" story changed much between
the time of the BoLT and the Silmarillion.
As the stories developed, Gothmog, no longer the son
of
Melkor, became the slayer of Feanor. Then in the Battle of Unnumbered
Tears
it was Gothmog who slew Fingon and captured Hurin.
In the Return of the the King, in the Third
Age of the Sun, Gothmog was the name of the lieutenant of Minas Morgul.