The Balrogs, or Balrogath ("Balrog-kind") were Maiar corrupted by Morgoth during the creation of Arda, who cloaked themselves in shadow and flame and carried whips and swords. Famed Balrogs include Gothmog, slain by Ecthelion, and Durin's Bane, slain by Olórin (Gandalf).
Powers and Stats
Tier: Likely 6-B
Origin: Lord of the Rings
Classification: Corrupted Maiar, Demon of the Ancient World
Powers and Abilities: Superhuman Physical Characteristics, Fire Manipulation, Magma Manipulation, Darkness Manipulation, Elemental Manipulation (Can craft weapons from their own beings), Shapeshifting, Flight, Immortality (Types 1 and 2), Expert Sword and Whip Wielders, selective Intangibility.
Attack Potency: Likely Country level (Balrogs were described as some of the most dreadful servants of Morgoth, which included high-tier Maiar like Sauron. Seven Balrogs were able to drive away a starving Ungoliant, who overpowered a weakened Morgoth. All Balrogs are Maiar, and remain very powerful)
Lifting Strength: Unknown
Striking Strength: Likely Country Class (Seven Balrogs attacking together managed to hurt Ungoliant. Durin's Bane destroyed part of a mountain merely from clashing with Gandalf)
Durability: Likely Country level (Durin's Bane survived falling to lower Moria and having an incredibly long fight with Gandalf, who was one of the strongest servants of Manwe. Balrogs were the greatest force in Morgoth's army, even more powerful than dragons. At least comparable to Tilion)
Range: Extended melee range with whips and swords
Standard Equipment: Swords and Whips
Weaknesses: Holy water to a limited extent.