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. On the other hand, the player has a new advantage over them: they can be caught by the Ionized Plasma Levitator (also known as the grabber). 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.
|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