Doom Reference 1
This is my first attempt at a 'splatbook' a resource and reference submission for the Cosmic Era setting using the basic material from the original DOOM game.
Still clad in their UAC issue fatigues, the zombies are the corpses of slain mercenaries and security troops who have been animated by the strange radiation emitted by arcanotech devices. Alternately, they can be the product of a storm breach, where the corpses of the dead are reanimated by the incorporeal entities that live in the toxic realms sandwiched between mathematical potentials. Unlike traditional zombies, these undead retain a degree of intelligence and can still use firearms and perform tasks like manually opening doors, using melee weapons and cooperating with each other. These skills are nowhere near optimal ability, nor are they able to communicate in anything but the most base and rudimentary gestures and guttural animalistic noises. Zombies will never parlay with the living, nor are they affected by things like diplomacy or seduction.
Defensive stats are high, and aside from headshots they are immune to critical hits. Their accuracy with weapons and other basic skills function at the lowest level. They are also strong in hand to hand combat, and are hungry for human flesh, and are attracted to fear and loud noises.
Some zombies are just a step above the usual undead who are often associated with alien artefacts and strange radiations. The Zombie commando is a superior soldier, typically special forces, elite quality regular troops, mercenaries or otherwise strong willed and capable soldiers. Who happen to be dead at the time. The Zombie commando is still equipped with a UAC issued standard light armor suit and likely with superior grade weaponry like the deadly and effective mag guns.
In addition to having better firepower and stronger armor, Zombie Commandos are animated by stronger and more competent infernal entities, giving them greater skill with their weapons and other abilities. Zombie commandos are able to innately lead groups of lesser zombies, functioning as an officer and organizer to their hoard. They have high durability, and better initiative in combat.
Infested Armored Troopers
Power armor is common in the Cosmic Era, and it only takes the trooper inside the metal shell to die for him to reanimated as an infested armor trooper. The same strange energies power the armor that drag the corpse back to movement and life. Armored troopers have the same functional stats as normal power armor, but the pilot inside is immune to critical hits or other strategies that damage the pilot and not the machine. Infested troopers still have their heavy guns, though these usually have a fair chance to be out of ammo by the time they are reanimated. Most troopers are armed with melee weapons or infernally powered energy weapons.
Troopers, while very very tough, are not the brightest of undead, and function on the same level as basic zombies, including subservience to zombie commandos. Zombie power armor troopers are not in DOOM, but the commonality of power armor and the infested terran from Starcraft provide reason and background references.
The Imp is usually the most powerful form of infernal spawn that most military and security forces can reasonably expect to encounter and not be butchered instantly by. Imps were formerly humans whose corpses were reanimated by exceptionally strong infernal forces. The resulting possession caused the corpse to explode outward in a mass of cancerous growth. This causes a general increase in size, strength, and durability. Body mass roughly doubles (though some grow a good deal larger) and this growth is often fueled by consuming other corpses or still living victims. Bone spurs, claws, and other bony growths and functional body barbs are commonplace among imp mutations.
Imps can heal themselves fairly rapidly, and have greater than expected strength, making them a threat to even power armored troopers if they are not cautious when facing imps in combat. Unlike other undead, imps do not use any human made weapons, and their transformation typically destroys any armor they might have been wearing before. The majority of imps demonstrate limited parapsychic ability with pyrokinesis (direct attack only) being the most common.
The Demon is an uncommon appearing infernal creature. They are large, incredibly muscular and physical foes, aggressive and stunningly violent foes. Possessing a mixture of vaguely humanoid and disturbing animal traits, demons are strong enough to rip humans limb from limb bare handed, and to dismantle an armored trooper with their tremendous strength. Rather than being a specific creature, the demon is a generalization. Thus far the various demons encountered have been unique in appearance, rather than appearing as a specific infernal race, such as the Tarxan.
Demons have supernatural endurance and toughness and are able to shrug off lower power weapons with ease and can generally only be brought down with high energy weapons, magnetic guns, or powered melee weapons. They do not use any ranged weapons, other than throwing things. They will use improvised weapons such as clubs and stabbing implements when present, and their prey required a can opener.
Baron of Hell
Barons of Hell are massive creatures, physically larger than power armor troopers, stronger, and much tougher. Where the 'general' run demon can be brought down by power armor mag rifles, the Baron of Hell requires the sort of heavy firepower brought to bear by heavy weapons troopers, anti-armor weapons, or other heavy grade, big bore firepower. Barons of Hell are malicious, cunning, and intelligent, able to converse in a variety of languages, and can control undead with a whim. They have an innate understanding of arcanotech technology, finding it familiar and comforting to be around. This means that they gravitate towards areas where there are large amounts of such technology and devices, be they alien, man made or something else completely different.
The Baron of Hell disdains human made weapons, except for powered melee weapons, which they have a certain romantic fondness for. They are all parapsychic capable and conjure green flame, can mind control weak willed individuals, and performs feats of body warping, mutation, and otherwise ruin someone's day for their fun an amusement.
The Cacodemon is a hyperdimensional creature, existing on a greater number of planes than humans and even other infernal beings. It only extends its head into the physical realm, leaving (thankfully) the bulk of its body in the arcane planes where it exists more fully. Cacodemons are vocal and make a great deal of noise, hissing, spitting, and constantly releasing a stream of vitriol, blasphemy, and insults. Their hyperdimensional nature allows them a degree of insight to the creatures around them, so often this stream is tailored to the creature nearest to them. This is highly unsettling as Cacodemons are able to pluck random facts and thoughts from the mind/spirit of other sentient beings. In combat, they can be brought down with conventional weaponry, though this is more them just retracting their heads back, leaving behind a good deal of gore. They have an acidic saliva attack, and a nasty bite that is able to damage power armor.
The good news is that this is all they can do. If the Cacodemon ever extruded its entire mass into the physical realm, they would physically be on par with light mecha, and are large, strong, and aggressive. Other infernal creatures have an innate dislike of Cacodemons, and they do not work together. Demons and Barons of Hell will work to drive them back to where they come from, and cacodemons have no ability to control undead.
The Lost Soul is a disturbingly common infernal creature, especially in locations away from Earth. The floating skulls, wreathed in flame are easily destroyed with firearms, even civilian grade weapons. They can also be shattered with melee weapons. Their flames do create illumination, but the flame is heatless, and cannot set combustible materials on fire. Seemingly suicidal, Lost Souls are drawn to living organisms, attacking them with a short range telekinetic strike. They can bite, but this is rare, as their ability to inflict harm by will suits them better.
Lost Souls are a hyperdimensional form of undead, and the damage inflicted by them is punching and kicking from their astral form which they can only manifest long enough to inflict damage. They are servants of the Cacodemons, and serve them as shock troops.
Spider Demon or Arachnotron
The spider demon is a very rare, but very tough infernal creature. Unlike other infernal creatures, spider demons don't manifest a physical body when breaching the material realm, they create a body out of available materials, and these bodies are always composed of both organic material, and arcanotech devices. The body plan is always the same, four to eight mechanical legs and an armored pod/chassis with weapons and other arcanotech devices clustered around the front. The organic component forms the body/abdomen of the mechanical horror. Spider demons are super intelligent, and are fully capable of using the tech they have gathered to make their new bodies. They are also capable of interacting with the CogNet, engaging in electronic warfare, and a number have demonstrated parapsychic powers, because having an armored tank body and plasma cannons just wasn't enough. Spider Demons particularly enjoy causing hallucinations, mind manipulation and control, and playing the worst sort of mind games and body horror games on victims they are able to reach. Like the Barons of Hell, they are conversant in many languages, and can and will speak with their victims.
Taking out the spider demon is difficult, and requires either dedicated armor-busting weaponry, heavy grade (mecha) weaponry, or getting close enough to use powered melee weapons to take them apart. All of these are difficult options as spider demons can use their own weapons, use psychic blasts and psychic assault abilities, and have good armor protection.
The most dangerous and horrific combination of infernal might and arcanotech, the Cyberdemon is a foe that few have encountered. The Cyberdemon towers over power armor troopers and is large enough to physically threaten mecha and armored vehicles. It has full body armor, a mix of subdermal modification and external armor. The cyberdemon is fast, aggressive, and unlike the Barons of Hell, which it strongly resembles, it is mute and doesn't communicate or play any of the other games that infernal agents are prone to. The Cyberdemon is a death engine that can only be stopped with heavy high energy weaponry, large bore cannons, and other weapons generally intended to stop mecha or shoot down aerospace craft. Cyberdemons are equipped with extensive electronic sensors and have demonstrated the ability to accurately engage and shoot down aerospace and helocraft. They can be jammed, and can also engage in active counter-jamming of their own.
The Cyberdemon was once a Baron of Hell. The demon was subjected to their own genetic modifications, then grafted with weaponry and armor, and electronics wired directly into their brain to turn them into the supersoldiers of Hell. They do not speak, as they are actually in regular communications with other demons who have access to the telemetry from the Cyberdemon's hardware. The amount of personality left in a Cyberdemon is debateable, and it isn't known if the Cyberdemon is self aware, or if it is little more than a meat puppet controlled remotely by another being.
Cyberdemons are manipulated and controlled by spider demons, who supervise their construction and maintenance. The cyberdemon is a tormented creature that would turn on it's arachnotron master in a heartbeat if it could. They were barons of hell who were captured and subjected to said augmentations against their will by the spider demons.