Overview
Doom
Lost Souls float around at a leisurely pace until they find someone to attack, at which point they launch themselves toward them at high speed with a hiss, the only thing that could alert someone to their presence. Their quiet nature makes them proficient at surprising careless players. The Doom manual describes Lost Souls quite bluntly as “Dumb. Tough. Flies. On fire. ‘Nuff said.”
Doom 3
In Doom 3, Lost Souls are a bit more fleshed out than before. Literally. Doom 3 Lost Souls are human heads mounted on rocket contraptions with their jaws torn open wider than humanly possible with their teeth having become long, sharp, and needle-like.
The first Lost Soul encountered as an enemy appears in a grotesque cutscene where a woman the player encounters whispers “help me,” after which her skin starts to shrivel inwards and a Lost Soul then suddenly bursts out of her head, ripping out her spine in the process. Whether this is standard for the spawning of a Doom 3 Lost Soul or a unique case is uncertain as no other Lost Soul is seen doing this, but it makes for a disturbing but plausible theory.
Powers & Abilities
Lost Souls attack by launching themselves at opponents and then burning and biting them. They launch in a straight line though, and can therefore be dodged if carefully anticipated. Lost Souls are rarely alone however, and can prove overwhelming when they swarm at the player in a pack. If attacked from a distance, Lost Souls are also capable of dodging incoming fire. While not very tough and relatively easy to kill, Lost Souls are nothing to underestimate.