The Forgotten One's form is an echo of the original lost soul's shape in the classic Doom games, replacing the reinterpretation that appeared in Doom 3. It is a flying skull with two demon horns, and floats with a stream of flame behind it. Its only attack consists of flying towards its enemy and biting. Unlike the lost souls in Doom 3, Forgotten Ones do not moan and scream upon detecting the player, but instead make a high pitched whistling sound similar to the call of a red-tailed hawk.
The Forgotten One has the same strength as the lost soul in terms of health, with the potential to withstand a standard shotgun blast from mid-range. However, they are also more predictable, as their charge attacks are slightly slower and there appears to be a slight lag when they initiate their charge attacks. The machine gun and pistol are solid choices when facing them at mid-to-long range, with only two pistol shots or three machine gun bullets required to kill one. However, Resurrection of Evil also introduces a new weapon that gives the player a new advantage over them: they can be caught by the Ionized Plasma Levitator (also known as the grabber). It is wise to hold the trigger for the grabber before the Forgotten One enters the weapon's range, which will allow it to be caught in the tractor beam as soon as it enters range - it is not necessary to time the trigger press as it is with conventional weaponry. Once grabbed, they can still potentially fight the beam and cause damage, so it is best to immediately shoot them away, which disintegrates them. They are not as maneuverable as the lost soul, being less capable of bending their trajectory in mid-flight, and taking longer to recover if their attack misses.
The forgotten replace lost souls from the original game as a small flying enemy and are moderately common.
The enemy count on Nightmare is the same as on Veteran.
A small number of Forgotten Ones inhabit the Enpro Plant while the Bravo Team survivor traverses the walkways, and more are encountered in Hell.
|Monsters from Resurrection of Evil
|From Doom 3: Arch-vile | Cacodemon | Cherub | Commando | Demon | Hell knight | Imp | Maggot | Mancubus | Revenant | Tick | Trite | Wraith | Zombie | Z-Sec
New hellspawn: Bio-suit zombie | Bruiser | Forgotten One | Vulgar
New bosses: Helltime Hunter | Berserk Hunter | Invulnerability Hunter | Maledict