The army was assembled in FA 510 after Maeglin's betrayal under the leadership of Gothmog. The army appeared to be the most advanced in technology compared to the rest of the Glamhoth. It was made up of Orcs, Trolls, Werewolves, Dragons, and Balrogs. They surrounded the city and besieged it killing nearly all save for the few that followed Tuor and Idril.
The Orcs in Gothmog's Army were likely armed with pikes and Scimitars; Trolls were possibly armed with hammers and clubs; Balrogs were armed with fiery whips. But in older versions, they also used iron machines fueled by "internal fire" as personnel carriers and destroying fortifications. They also might have used the explosive devices, Crossbow, and ballistas used later by Saruman's army in the Battle of the Hornburg in the Third Age.