Gothmog was Lord of the Balrogs during the First Age, captain of Angband and equal to Sauron, both serving Morgoth.
Gothmog was a Maiar and he pledged his allegiance to Melkor.
He is responsible of killinf Feanor in the battle of Dagor-nuin-Giliath in YT 1498. After that, Gothmog reappeared as a general of Angband in several more major conflicts, including the Dagor Aglareb and the Nirnaeth Arnoediad. HE then again killed a high king of the Noldor, Fingon, and after that, captured Húrin, father of Túrin Turambar, and dragged him back to Angband.
In FA 510, Gothmog was killed by Ecthelion, ending the battle of Gondolin where both died drowned in the Fountain of the king.
