Forgotten One

The Forgotten One's form is an echo to the original Lost Soul's shape in the previous Doom games, excluding its form in Doom 3. It is a flying skull with two demon horns, and floats with a stream of flame behind it. Its only attack is flying towards its enemy and biting. The Doom 3 incarnation of the Lost Soul does not appear in the expansion pack, having been replaced by The Forgotten One.

Due to the lack of melee weaponry, these enemies are much more difficult to eliminate from the original. As in Doom 3, the use of the chainsaw or weak weaponry can result in immediate death, however this incarnation has the potential to withstand a standard shotgun blast.