In the First Age, in Angband, there were many creatures bred and twisted by darkness.
Ancient Evil are creatures that served Morgoth (Sauron's master) in Angband prior to Morgoth's expulsion from the world. In later Ages, the Dark Lord Sauron bred from these abominations new creatures with which to make war upon Middle-earth. They have been returning from their dark hiding places to join the wars on the free peoples. Many are often found in caves, and some have become promient leaders of the forces of dark.
This category includes such creatures as the merrevail, gaunt-men, and Balrogs. Ancient Evil creatures are found across Middle-earth. They are always aggressive. They are weak to Beleriand and sometimes Westernesse damage; resistant to Common damage and often to Tactical damage.
THe types of Anciet Evil beings that have been reported: