DOOM: Pain Elementals and Lost Souls

UAC Demonic Entity Log: 007- Pain Elemental

One of the most solitary and rare demon species to be seen on Earth have been dubbed the Pain Elementals. Resembling large floating tumors, Pain Elementals are pretty docile and don't tend to attack unless provoked. However, the air around them reeks of disease and decay with their aim being to spread this air around the globe. Due to this, they are deemed responsible for the sickness that wiped out much of the Earth's population following the demonic invasion. With the fleshy masses' stomachs acting like furnaces, this gives them the ability to drift in the air like that of the Cacodemons, though inside a Pain Elemental's body is something equally as disturbing as its outward appearance. 

Note 007A: An interesting anecdote; Researchers have speculated that Pain Elementals have been represented in artwork before, appearing as what art historians call "Hell Mouths".

Note 007B: The Pain Elementals sometimes appear to have vestigial arms or other limbs attached to their bodies, seemingly useless. 

UAC Demonic Entity Log: 007.2- Lost Soul

Brewing inside Pain Elementals' stomachs are the Lost Souls, spirits resembling infants that have perished in childbirth, due to physical deformation. When provoked, Pain Elementals will spew out a grouping of Lost Souls to retaliate against an attacker, their malformed heads covered in a billowy flame. Lost Souls travel exceptionally quick, and attack in swarms. Finding a corpse of a Lost Soul proved to be impossible, as they explode upon extermination, completely eviscerating any remnants. Any evidence of these manifestations is based on descriptions and renderings by the research team, as they unexplainably fail to appear in photographs and film. 

Note 007.2A: To go along with the notion that the demonic army is craftier than originally anticipated, many of their physical appearances seem to fuel the idea of "Spiritual Warfare". If these spirits are indeed the souls of infants, they're doing a good job of making their Enemy look less merciful, planting seeds of doubt in believers. With no physical specimens preserved, it could be argued that the Lost Souls are artificially designed and birthed for this very purpose.