Monster


 * "Hellspawn" redirects here. For "Team Hellspawn", see Doom voxel project.

In the Doom franchise, a monster is any artificially intelligent entity that is not spawned if the -nomonsters parameter is used. In single player and cooperative games, much of a user's playing time is spent in combat with enemy monsters. Monsters are either placed in a level during its design, created by another monster (particularly, the Pain Elemental spawns Lost Souls), or spawned by the final boss.

Any monster placed in a level or created by the final boss is initially dormant and becomes active only when it sees a player, when it sustains a damaging attack, or when it hears a player attack, even if this is with the (otherwise silent) fist. When activated, a monster will advance on its target and attack, sensing the location of the thing they are after even if it is out of sight, and advancing toward that location even if it is on the other side of the level. If a monster hits an obstruction during its hunt for its target, it will attempt to walk around it or float around/over it (Cacodemon, Lost Soul and/or Pain Elemental). Monsters that have been alerted normally remain active indefinitely, even after respawning or being resurrected by an Arch-vile. However, there is a bug which returns any active monsters to a dormant state if the user re-loads a saved game. In general, monsters of different types can accidentally hurt each other and will often turn against each other in such cases, engaging in monster infighting. If a monster defeats an aggressor without ever seeing or hearing a player, it will return to a dormant state.

Monsters can use some types of teleporters, although they do so accidentally or unintentionally, as their intelligence is very limited. Monsters can similarly activate lifts and open certain doors, although some monsters may not fit through doors and openings that are just large enough for the player. Monsters can be hurt and killed by crushing ceilings, but are unaffected by all forms of damaging floors.

The monsters can be classified into two groups: the former humans, or zombies, possessed by demonic forces, and the demonic monsters (demons, hellspawn, or mortally challenged) originating in Hell or arriving from there.

Doom
Doom and its retail extension, The Ultimate Doom, include the following monsters:
 * Zombieman - A former soldier who is now a demonically possessed zombie, armed with a rifle. The weakest of the enemies in Doom and therefore, the easiest to kill.
 * Shotgun Guy - A former sergeant ranked soldier who is now a demonically possessed zombie, armed with a shotgun. They are more dangerous and skilled than their Zombieman counterpart.
 * Imp - A brown, human-sized humanoid demon that hurls fireballs from a distance and claws nearby opponents. They are the most frequently encountered monsters.
 * Demon (Pinky) - A large humanoid, bipedal demon with a large mouth, armed with sharp teeth. While only limited to melee, they can outrun their prey most of the time, and can occasionally come in packs.
 * Spectre - Identical to the Demon (Pinky), except that it is partially invisible.
 * Lost Soul - A floating, flaming skull that can rush quickly to bite their opponent.
 * Cacodemon - A large red floating spherical monster with horns, one eye, and a Cheshire cat smile. It moves relatively slowly, but has strong jaws and spits out "lightning balls" from a distance.
 * Baron of Hell - Two of these monsters act as the boss in Knee-Deep in the Dead, resembling large blood red Satyrs. It can hurl streaming balls of green plasma and employs a powerful clawing attack at close range. They can take enormous punishment before being slain.
 * Cyberdemon - This massive cybernetic minotaur appears as a boss in The Shores of Hell. It will fire a volley of three explosive rockets from the rocket launcher mounted on it's left arm, while moving at a relatively rapid rate for its size. It can easily lay waste on even the toughest mortal who has the guts to challenge it, while being able to easily withstand most attacks from it's high health.
 * Spider Mastermind - This cybernetic boss awaits in Inferno and Thy Flesh Consumed. It appears as an enormous brain with eyes, a mouth, and comparatively small arms, atop a four-legged metal chassis with an incorporated triple-strength chaingun which will mow down the unwary to bits within moments.

See also Player and Barrel.

Doom II
Doom II (and Final Doom) includes the same monsters as Doom in addition to the following monsters:
 * Heavy Weapon Dude - A tough, corpulent zombie with darker skin and red armor, he will rapid fire with his chaingun to quickly proliferate his targets.
 * Revenant - A tall, armored human skeleton-like armor that can launch guided missiles and punch opponents at close quarters. These are the results of recycled demon combatants.
 * Hell Knight - Identical to the Baron of Hell but tanned in color, emits higher-pitched sounds and endures only half as much damage.
 * Arch-vile - Infernal High Priest who can conjure flames to attack. Even worse, it can also resurrect dead monsters.
 * Arachnotron - Strongly resembles the Spiderdemon, but is much smaller and weaker and is armed with a plasma gun that fires green bursts.
 * Mancubus - A grotesquely bloated humanoid whose forearms are replaced with a pair of flamethrowers. It moves slowly, but nonetheless possesses potent attacks from it's flamethrowers while withstanding a fair amount of ordinance to bring down.
 * Pain Elemental - A large floating spherical monster that resembles a Cacodemon, except being brown in color and has small arms. It attacks by spitting Lost Souls at its target, and even creates a few more as it dies.
 * Icon of Sin - A giant demonic entity that takes the appearance of a biomechanical goat mounted on a wall, with an exposed brain which shoots cubes that spawn the lesser demons. Though not technically a monster, it acts as the de facto leader of all the other monsters, in which the protagonist must defeat to win the game.

Cameo enemies:


 * Wolfenstein SS - A Nazi Schutzstaffel trooper in blue uniform. Found exclusively in the two Wolfenstein-themed secret levels and attacks with a medium-strength machine gun.


 * Commander Keen - A hanged effigy of the cosmonaut from id Software's pioneering series of games only appearing in MAP32: Grosse. It neither moves nor attacks, although killing all four Keen figures is necessary to reveal the exit switch and finish the level.

Newer Doom franchise games
The newer games of the Doom franchise generally include a set of monsters from the PC Doom games or inspired on them and possibly a number of new creations. Various ports include the same sprites as their predecessors, although some change their appearances either to achieve a new style (such as in Doom 64) and the newer games (such as Doom 3) provide polygonal versions that suit their more advanced technology and rendering capabilities.

Doom RPG
Doom RPG features almost all of the monsters from Doom II, with the exception of the Shotgun Guy, Spectre, Arachnotron, Wolfenstein SS, Commander Keen and Spiderdemon (as well as the final boss).

Returning Monsters(with variants):


 * Zombie Private - Zombie Pvt is the first version of the Zombie class encountered in Doom RPG.
 * Zombie Lieutenant - Zombie Lt. is the second version of the Zombie class encountered in Doom RPG.
 * Zombie Captain - Zombie Cp. is the third version of the Zombie class encountered in Doom RPG.


 * Troop - Troops are the least powerful of the Commando class in Doom RPG.
 * Commando - Commandos are the 2nd most powerful of the Commando class in Doom RPG.
 * Assassin - Assassin are the most powerful of the Commando class in Doom RPG.


 * Impling - The Impling is the weakest form of Imp.
 * Imp - The Imp is the 2nd strongest form of Imp.
 * Imp Lord - The Imp Lord is the strongest form of Imp.


 * Phantom - Phantoms are the weakest of the Lost Soul class of monsters in Doom RPG.
 * Lost Soul - Lost Souls are the 2nd strongest of the Lost Soul class of monsters in Doom RPG.
 * Nightmare - Nightmares are the strongest of the Lost Soul class of monsters in Doom RPG.


 * Bull Demon - Bull Demons are the weakest form of Demons class of monsters in Doom RPG.
 * Pinky - Pinkies are the 2nd strongest form of Demons class of monsters in Doom RPG.
 * Belphegor - Belphegors are the strongest form of Demons class of monsters in Doom RPG.


 * Malwrath - The Malwrath is the weakest of the three Cacodemon class of monsters in Doom RPG.
 * Cacodemon - The Cacodemon is the 2nd strongest of the three Cacodemon class of monsters in Doom RPG.
 * Wretched - The Wretched is the strongest of the three Cacodemon class of monsters in Doom RPG.


 * Beholder - The Beholder is the weakest of the three Pain Elemental class of monsters in Doom RPG.
 * Rahovart - The Rahovart is the 2nd strongest of the three Pain Elemental class of monsters in Doom RPG.
 * Pain Elemental - The Pain Elemental is the strongest of the three Pain Elemental class of monsters in Doom RPG.


 * Ghoul - The Ghoul is the weakest of the three Revenant class of monsters in Doom RPG.
 * Fiend - The Fiend is the 2nd strongest of the three Revenant class of monsters in Doom RPG.
 * Revenant - The Revenant is the strongest of the three Revenant class of monsters in Doom RPG.


 * Behemoth - The Behemoth is the weakest of the three Mancubi class of monsters in Doom RPG.
 * Mancubus - The Mancubes is the 2nd strongest of the three Mancubi class of monsters in Doom RPG.
 * Druj - The Druj is the strongest of the three Mancubi class of monsters in Doom RPG.


 * Infernis - The Infernis is the weakest of the three Arch-vile class of monsters in Doom RPG.
 * Arch-vile - The Arch-vile is the 2nd strongest of the three Arch-vile class of monsters in Doom RPG.
 * Apollyon - The Apollyon is the strongest of the three Arch-vile class of monsters in Doom RPG.


 * Ogre - The Ogre is the weakest of the three Baron class of monsters in Doom RPG.
 * Hell Knight - The Hell Knight is the 2nd strongest of the three Baron class of monsters in Doom RPG.
 * Baron of Hell - The Baron of Hell is the strongest of the three Baron class of monsters in Doom RPG.

New Monsters:


 * Hellhound - The Hellhound is a monster found in Doom RPG belonging to a demonic class known as Canines. Hellhounds are brown members of the species.
 * Cerberus - The Cerberus are second type of Canine encountered in Doom RPG. They are first encountered in Sector 3.
 * Demon Wolf - Demon Wolf is the third and most powerful form of the canine class of monsters in Doom RPG. It can be found beyond the secret green door in Sector 1.
 * Kronos - Kronos was a UAC scientist working on teleportation research. He supposedly travelled to a dimension of pure evil where he combined human technology with demon flesh to create the Cyberdemon. In Reactor, the last level of Doom RPG, it is revealed that Kronos has been changed into a demon

Non-boss enemies in Doom RPG are organized into classes. For example, there are three types of Imps, while the Hell Knight and Baron of Hell both belong to the "Baron" class. Monsters in the same class use the same sprites, but are somewhat differently colored and vary in difficulty.

Doom II RPG
The Doom RPG sequel Doom II RPG has almost the same enemy entity set as Doom RPG, but adds a few of its own, even adding a few boss entities. The game adds the following new enemy types:


 * Lesser Sawcubus - The L Sawcubus is a monster found in Doom RPG belonging to a demonic class known as Sawcubus species.
 * Greater Sawcubus - The G Sawcubus is a monster found in Doom RPG belonging to a demonic class known as Sawcubus species.
 * Chainstrosity - The Chainstrosity is a monster found in Doom RPG belonging to a demonic class known as Sawcubus species.


 * Brier - The Brier is a monster found in Doom RPG belonging to a demonic class known as Sentinal species.
 * Watcher - The Watcher is a monster found in Doom RPG belonging to a demonic class known as Sentinal species.
 * Sentinel - The Sentinal is a monster found in Doom RPG belonging to a demonic class known as Sentinal species.


 * Zombie Civilian - The Zombie Civilian is a monster found in Doom RPG belonging to a demonic class known as Zombie species.
 * Zombie Worker - The Zombie Worker is a monster found in Doom RPG belonging to a demonic class known as Zombie species.
 * Zombie Tech - The Zombie Tech is a monster found in Doom RPG belonging to a demonic class known as Zombie species.
 * Sentry Bot - The Senrty Bot is a monster found in Doom RPG belonging to a demonic class known as Bot species.
 * Pinkinator - The Pinkinator is a demon and the first boss in Doom II RPG that spawns Pinky demons.
 * VIOS - VIOS (Virtual Icon Of Sin), is an AI of demonic origins and the main antagonist of Doom II RPG.

In addition to the new classes of enemies, the game has two new boss class entities; the Pinkinator and VIOS. All the sprite artwork used for the enemies was hand-drawn specifically for this game--even for "classic" monsters returning from previous games in the series--in order to allow for higher-resolution sprites than what was used in the original Doom games (though the higher-resolution sprites are only used on higher-end devices).

Sony PlayStation
The official port of Doom to this platform removes the Arch-vile but includes an additional monster over the PC versions.
 * Nightmare Spectre - Nightmare Spectres are dark cyan-tinted, faster and more powerful forms of Spectres.

Doom 64
Doom 64 includes newly illustrated versions of the Doom and Doom II monsters, created from high-poly rendered models rather than sculptures or hand-drawings. Revenant, Heavy Weapon Dude, Arch-vile, Spiderdemon, Wolfenstein SS, Commander Keen and final boss are not present.

Returning Monsters:


 * Zombieman - They are made from systematically altered dead carnage remade back into corrupted living tissue. The mutations were devastating. The demons have returned stronger and more vicious than before.
 * Shotgun Guy - Much like the Zombiemen, he was once a marine, always a marine... Except in this case.... These guys may look like your old buddies the Zombiemen.
 * Imp - This Imp heaves balls of fire down your throat and takes several bullets to die.
 * Lost Soul - These variations of the Lost Souls look somewhat different, in their new mutations they have become slightly transparent, and there is fire only on the top of their skulls
 * Demon (Pinky) - Sorta liked shaved gorillas, except with horns, big heads and lots of teeth. They don't kill easily. Get to close and they'll rip your sorry head off.
 * Spectre - In Doom 64, inactive spectres are initially rendered as opaque Demons with a green tint, becoming translucent upon detecting the player.
 * Cacodemon - It underwent major mutations, becoming beige-brown, with a single yellow-green eye, and gaining two arms with broken chains attached, and a rather terrifying face.
 * Pain Elemental - With further altering from mutations it is colored dark pink (like the original Cacodemon while the Doom 64 Cacodemon was colored beige brown and had two arms), has a green eye and in place of its arms are two mouths so it can now spawn two Lost Souls at the same time.
 * Arachnotron - This left them considerably altered; the mechanical body is much bigger, with the brain head ducked down inside the machine itself instead of sitting atop it.
 * Mancubus - Their pupil-less eyes have blue sclera instead of green, their bodies have less fat and a more bear-like face, they are taller and wear a metal body harness. Their fireballs are smaller and appear more like fiery brimstone.
 * Hell Knight - Though overall similar to the standard hell knight, the mutated variant found in Doom 64 is less pale in color.
 * Baron of Hell - It's mutations have given it a red-orange colour scheme (rather than greenish which is instead used for the Hell Knight).
 * Cyberdemon - It has not gone through many changes and mutations except that it has darker colored skin, a more bovine-esque head structure (though the face is very canine-like appearance), is slightly stronger and much larger, with thicker wiring running along its robotic body parts.

New Monsters:


 * Nightmare Imp - The Nightmare Imp is a translucent blue/purple Imp which is faster than the standard Imp variant
 * Mother Demon - The Mother Demon appears as a large demonic larva with dead black eyes with red irises, four arms, a skull-like face and smallish mouth filled with many long, sharp teeth. It has no wings, yet moves by floating around.

Doom 3
Doom 3 includes its own versions of many monsters from the original games. Some of these, such as the Demon and the Hell Knight, are considerably different from their predecessors.

Returning monsters:


 * Zombie - Former UAC civilians now possessed by evil spirits, they slowly close in to claw their victims
 * Fat Zombie - A Zombie that is obese, granting them higher health and damage, at the expense of speed.
 * Flaming Zombie - Also known as "Bernie" for short, it is a Zombie that is set on fire, sprinting a lot quicker and possessing more health.
 * Morgue Zombie - Similar to the Boney Zombie but has underwear, less skinny, and can move quicker than most Zombies.
 * Chainsaw Zombie - Also known as "Sawyer", it is a tough, muscular Zombie who wields a chainsaw to mow down its victims.
 * Boney Zombie - Also known as "Living Dead" by researchers, they are naked, partially decayed zombies, found only in Hell.
 * Zombie Security (Z-Sec) - Former UAC security guards who are now possessed by evil spirits. They can utilize firearms and rely on defensive tactics to take out their target.
 * Imp - The most common monsters encountered, they are tall humanoid creatures with grey skin and 10 small eyes. They launch fireballs at a distance and claw at close range, but are also subject to leaping and pouncing on their target.
 * Demon (Pinky) - A large canine-like quadruped demon. They are armed with tusks and sharp teeth and will quickly close in on their victim to launch a biting attack that can disorientate their victims.
 * Lost Soul - A small flying demon consisting of a human head mounted on a flying rocket engine contraption. They come in swarms and will charge right at their target.
 * Cacodemon - A large airborne demon that fires a giant missile at a distance, while biting their victims at close range.
 * Revenant - A tall human skeleton-like demon armed with a pair of shoulder-mounted missile launchers that fire relatively slow-moving homing missiles. They will also resort to clawing and punching at their enemies up close.
 * Mancubus - A very large, fat demon with fireball launchers for each arm, it alternates by firing one fireball from one of it's launchers before firing the second one. They will also resort to using all their strength to smash their victims up close with their launchers, making them tough, powerful, but nonetheless, slow.
 * Zombie Commando - Human marines transformed into demonic warriors. Aggressive and intelligent, they can easily overcome their foe with both strength and skill.
 * Arch-vile - A large, off-white colored humanoid demon, standing a head taller than a normal human even in its standard semi-crouched pose. They can launch large pillars of fire at their victims and summon lesser demons in the vicinity.
 * Hell Knight - One of the largest demons encountered, they launch green fireballs at a distance and can either claw or bite up close. They are aggressive and powerful, and will quickly overpower any smaller foe that stands in it's way.

Additionally, the following new monsters are encountered:


 * Maggot - A small demon that has two heads with long black tongues. Their back is hunched and consists of two large, tumor-like bloody stumps with retracting barbed bones protruding from them. They will close in on their victims to claw them, but are subject to leaping at great distance.
 * Trite - Small spider-like demons, with a body resembling an upside-down, human-like head and possessing six legs. They come in swarms and will either leap from a distance or bite at their victims up close.
 * Vagary - This demon has the lower half of a giant spider and the upper half of a woman. She relies on telekinesis by using loose objects on the ground to telepathically launch them at her targets.
 * Wraith - A small demon that possesses falx-like appendages on their arms, which they will use to attack their target. They possess a so-called "teleportation" ability, disappearing for a few seconds before reappearing several feet ahead of their previous position.
 * Cherub - A small demon resembling a human infant with insect-like wings. They come in swarms and will either claw or leap from several feet to powerfully pounce on their targets.
 * Tick - The Tick resembles Trites in terms of overall appearance and behavior. They are not as common and have different body appearances from Trites.

Boss monsters:


 * Guardian of Hell - This crocodilian-like demon stands more than 15 feet tall, and will ground pound to summon large 8 balls in it's vicinity while summoning it's Seekers.
 * Seeker - Small floating creatures that emit a tiny headlight, acting as spotters for the blind Guardian of Hell to seek their target. Appearing in a group of three, destroying them will leave the Guardian vulnerable.
 * Sabaoth - Sergeant Kelly's final state of his demonic transformation, where his lower half has been replaced with a tank-like vehicle, and upper half being a twisted body attached to heavy machinery armed with a very sharp claw. He relies on the BFG he has looted from Campbell while using his sharp claw to brutally strike his victims.
 * Cyberdemon - A large minotaur-like giant with a rocket launcher mounted on it's right arm, guarding the final portal to Hell in the Caverns. It will either fire three rockets at it's victims, or brutally stomp them to death with it's cybernetic feet. Dubbed as "Hell's mightiest warrior", it can only be defeated by the Soul Cube.

Some concepts of monsters, one of which resembles the spider-like monsters from Doom and Doom II, were shown by id Software during development of the game but did not make it to the finished product.

Doom 3: Resurrection of Evil
All the monsters in Doom 3 appear in Resurrection of Evil, except the Sabaoth, Vagary, Cyberdemon, Guardian, Seeker, and Lost Soul. Additionally, some new monsters are included:


 * Bio-Suit Zombie - A Zombie that wears a yellow hazmat suit and a oxygen tank, only found in toxic radioactive areas that can pose a hazard to breathing. Behaves like regular Zombies but drops valuable oxygen tanks upon death.
 * Vulgar - A medium size quadruped demon with a monkey-like frame that primarily shoots green fireballs while resorting to leaping and clawing up close. Behaves very similar to Imps, except possessing much quicker attacks, at the expense of being weaker.
 * Forgotten One - Flying flaming skulls with two demon horns, it resembles the classic Lost Soul more than does its namesake.
 * Bruiser - A tall demon with a large muscular body in the vein of a Hell Knight and mechanical features of a Mancubus. It attacks by quickly firing a barrage of fireballs from it's twin flame launchers

Boss monsters:


 * Hell Hunter
 * Helltime Hunter - Resembles a hovering Hell Knight without legs, and can move from one part of the area to another using short bursts of incredible speed.
 * Berserk Hunter - Possesses a large, mouthless head with four small eyes, holes on its knuckles that hide large claws and has normal humanoid legs compared to the Hell Knight's digitigrade, goat-like legs.
 * Invulnerability Hunter - Possesses a larger body structure than a Hell Knight, and has a bulging, extremely muscular body with a blue aura surrounding it.
 * Maledict - The demonic reincarnation of Dr. Malcolm Betruger, whose head and neck is attached to the tongue of a giant skeletal wyvern-like demon. He can summon giant pillars of flames while summoning Forgotten Ones and throwing flaming meteorites from the air.

Doom (2016)
The Doom reboot features a lot of returning monsters from the previous three games.


 * Possessed - Essentially renamed zombies.
 * Possessed Engineer - Killing them causes them to explode.
 * Possessed Security - The only hitscan enemies of the game. Equipped with a highly resilient energy shield.
 * Possessed Soldier - Equipped with plasma guns.
 * Possessed Scientist - Common zombies.
 * Possessed Worker - Different skin for common zombies.
 * Unwilling - Different skin for common zombies that appear in Hell.
 * Imp - Far more agile than its classic version, capable of climbing up walls and leaping over large gaps. Can also charge their fireballs into more powerful versions.
 * Pinky - Covered in thick armor on their faces and have a charging attack, making players have to dodge and attack their vulnerable tails.
 * Spectre - The Spectre is identical to the Pinky, albeit with the added advantage of invisibility.
 * Lost Soul - Now explode upon impact.
 * Cacodemon - Their attacks now blurs the players vision.
 * Revenant - Now equipped with jetpacks and can unleash much larger barrages of rockets.
 * Hell Knight - Resemble their Doom 3 incarnation, but can no longer throw fireballs. Instead they have increased speed and agility to chase and pummel the player.
 * Mancubus - Now covered in armor plating that protects their chests, and can launch their flames in streams rather than just fireballs.
 * Baron of Hell - Are larger than more agile than previous appearances, easily capable of outrunning the player.

It also includes some new monsters.


 * Gore Nest - Not technically demons, but an important part of fighting them. Gore Nests appear as objects to be destroyed to remove "demonic presence" from areas. Destroying them summons a wave of demons.
 * Hell Razer - Similar to an upgraded Possessed Soldier, Hell Razers are demons with an arm cannon that fires a beam of Hell energy.
 * Summoner - They are similar to Arch-viles, but can float, travel at untouchable speeds, and have a revamped appearance.
 * Cyber-Mancubus - Mancubi with heavier armor, and shoot toxic slime rather than fire, at greater ranges.

Boss monsters:


 * Cyberdemon - A boss, with several new abilities, including a laser attack and a flame wall.
 * Hell Guard - A trio of bosses, biomechanical suits inhabited by Parasites. They have various flame and energy-shield based attacks.
 * Spiderdemon - Final boss, equipped with a plasma cannon, lasers, an electric attack and telekinesis.

Multiplayer includes two new demons for players to play as.


 * Harvester - A demon that absorbs life energy to fuel its attacks.
 * Prowler - Demons similar to Imp, but stronger and without the fireballs.

Doom Eternal
Doom Eternal features several returning monsters, along with a selection of new ones. In this game, they are split into one of five categories: ambient, fodder, heavy, super-heavy and boss monsters.

Ambient

 * Buff Totem - A new threat which continually summons empowered demons until it is tracked down and destroyed. The Buff Totem is completely immobile and must be destroyed with a melee attack.
 * Cueball - Similar to the Possessed Engineers from Doom (2016), the Cueball will simply stand in place and will become an explosive missile when damaged.
 * Tentacle - Tentacles can be found on certain levels. When approached, they will emerge from holes in the ground and damage the player. However, not all Tentacle holes contain a Tentacle.

Fodder

 * Zombie - Returning from previous games, the Zombies behave similarly to the Possessed from Doom (2016).
 * Mecha Zombie - These Zombies appear as red eyed skeletal versions of regular Zombies but utilises multiple mechanical implants and an inbuilt flamethrower/plasma blaster.
 * Soldier - The Soldier comes in two variants which resemble the Possessed Soldier and Security from Doom (2016):
 * Soldier (Blaster)
 * Soldier (Shield)
 * Unwilling - The Unwilling are back as normal enemies in Doom Eternal, and their bone armor is sleeker and almost covers the body head to toe.
 * Imp - Returning virtually unchanged from Doom (2016), Imps make up one of the main fight forces of the demonic invasion.
 * Gargoyle - The Gargoyle behaves similarly to the Imp, albeit with the ability to fly.
 * Lost Soul - Lost Souls are much rarer than in previous games, with them now almost exclusively being spawned by the Pain Elemental. Other than this, they behave as in Doom (2016).

Heavy

 * Maykr Drone - The only non-boss Maykr enemies in the game, they have highly resistant bodies but can be easily dispatched with headshots. They were originally Fodder enemies.
 * Prowler - Transitioning from the multiplayer mode of Doom (2016) into the campaign of Doom Eternal, the Prowler is like a bigger, stronger, teleporting Imp.
 * Revenant - The Revenant's shoulder-mounted rocket launchers can now be destroyed, preventing it from using its ranged attacks.
 * Whiplash - A new female demon with a snake-like lower body. The Whiplash is quick-moving and uses a combination of melee and ranged attacks.
 * Carcass - This deceptively tanky demon has the ability to summon shields which are similar to those of the shield Soldier.
 * Pinky - The classic Pinky returns in Doom Eternal with behaviour much the same to Doom (2016).
 * Spectre - The Spectre is identical to the Pinky, albeit with the added advantage of invisibility.
 * Cacodemon - The Cacodemon of Doom Eternal seems to have received a health buff from Doom (2016), however it can be easily staggered for a Glory Kill if a grenade is fired into its mouth.
 * Hell Knight - The Hell Knight returns from Doom (2016), albeit with a tweaked visual design and a more aggressive attack pattern.
 * Dread Knight - This variant of the Hell Knight is a faster, tough and all around meaner variation with twin arm-blades. It is able to use a number of area-of-effect and ranged attacks not available to the Hell Knight.
 * Arachnotron - Returning from Doom II, the Arachnotron is an agile and tough early-game demon. It has an automatic cannon on its back which can be destroyed with enough damage, or a single direct Sticky Bomb.
 * Pain Elemental - Returns from the classic Doom games. As before, it summons Lost Souls as its main form of attack.
 * Mancubus - In Doom Eternal, the twin arm cannons of the Mancubus serve as weak points. By destroying them, its attack patterns will be changed and the demon will be weaker overall.
 * Cyber-Mancubus - Returning from Doom (2016), the Cyber-Mancubus differs from the normal Mancubus in that its twin arm cannons can't be destroyed. This demon's armor can, however, be destroyed in a single Blood Punch.

Super Heavy

 * Baron of Hell - Returning from Doom (2016) with an entirely new design, the Baron of Hell is an aggressive and powerful enemy which can attack with a combination of ranged and melee attacks.
 * Arch-vile - The Arch-vile returns from the classic Doom games. In Doom Eternal, it behaves similarly to a Buff Totem by summoning and empowering demons for the Slayer to fight. This version of the Arch-vile can also summon a shield to protect itself from the front.
 * Doom Hunter - This surprisingly-agile demon is first encountered as a boss in the early game. The Doom Hunter has an energy shield which protects it from incoming damage and a hover-sled which must be destroyed before it can be killed.
 * Marauder - The Marauder is a powerful new demon type which uses an energy shield. He can only be damaged when performing a melee attack with his axe, shortly after his eyes flash green.
 * Tyrant - The Tyrant is the biggest and toughest of the standard demons. It resembles and behaves like a classic Cyberdemon.

Boss monsters

 * The Gladiator - A large shield-wielding boss with a two-stage boss fight. His shield mechanics behave similarly to the Marauder.
 * Khan Maykr - The leader of the Maykr race. She has a shield which must be depleted before she can be damaged with a Blood Punch.
 * Icon of Sin - An enormous monster, the Icon of Sin is a rather straightforward fight which simply needs to have its body parts destroyed to defeat it.

Ambient

 * Spirit
 * Giant Tentacle
 * Turret
 * Demonic Trooper

Fodder

 * Screecher Zombie
 * Riot Soldier
 * Stone Imp

Heavy

 * Blood Maykr
 * Whiplash Spectre
 * Cursed Prowler

Super Heavy

 * Armored Baron

Boss monsters

 * Samur Maykr
 * Trial of Maligog
 * Dark Lord

Other games based on the Doom engine
Games powered by a modification of the Doom engine include a particular set of monsters suiting their setting, style and game behavior. These monsters share various basic characteristics of the Doom game monsters but may show some differences, such as being capable of multiple types of ranged attacks or being subject to the additional possibilities of game scripting (namely ACS in Hexen).

Heretic

 * Disciple of D'Sparil
 * D'Sparil
 * Fire Gargoyle
 * Gargoyle
 * Golem
 * Golem ghost
 * Iron lich
 * Maulotaur
 * Nitrogolem
 * Nitrogolem ghost
 * Ophidian
 * Sabreclaw
 * Undead warrior
 * Undead warrior ghost
 * Weredragon

Hexen

 * Afrit
 * Brown chaos serpent
 * Centaur
 * Dark bishop
 * Death wyvern
 * Ettin
 * Green chaos serpent
 * Heresiarch
 * Korax
 * Maulotaur
 * Menelkir
 * Reiver
 * Slaughtaur
 * Stalker
 * Stalker boss
 * Traductus
 * Wendigo
 * Zedek

Strife

 * Acolyte
 * Bishop
 * Ceiling Turret
 * Crusader
 * The Entity
 * Inquisitor
 * Loremaster
 * Macil
 * The Oracle
 * Programmer
 * Rat
 * Reaver
 * Rebel Soldiers
 * Sentinel
 * Spectre
 * Stalker
 * Templar

HacX

 * Android
 * Buzzer
 * D-Man
 * ICE
 * Majong 7
 * Mechamaniac
 * Monstruct
 * Phage
 * Roaming mine
 * Stealth
 * Terminatrix
 * Thorn thing
 * Thug
 * Unnamed invisible enemy

Technical

 * Monster behavior
 * Monster infighting

Background

 * Models