Monster


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

In the Doom franchise, a monster is any artificially intelligent thing 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 possessed by demonic forces, and the demonic monsters (demon or hellspawn or if you want to be polite mortally challenged) originating in hell or arriving from there.

Doom
Doom and its retail extension, The Ultimate Doom, include the following monsters:
 * Zombieman: Once a marine or guard like the protagonist, now a green-haired, hell-possessed soldier carrying a rifle. The weakest of the enemies in Doom and therefore, the easiest to kill.
 * Shotgun Guy: A bald, more durable zombie in black armor with a shotgun. A bit tougher than the former human (perhaps due to his rank), but still very easy to gun down.
 * Imp: A brown, human-sized humanoid demon that throws round fireballs and claws nearby opponents.
 * Demon(Pinky): About the size of a gorilla, this muscular pink brute runs quickly on its two hind legs to bite opponents. While not an immediate threat on their own, when in groups they do have a tendency to try and outflank their targets.
 * Spectre: Identical to the Demon(Pinky), except that it is partially invisible.
 * Lost soul: A floating, flaming skull that can rush quickly to gore an opponent.
 * Cacodemon: A large flying head-like monster with red scales, horns, and one eye. It moves relatively slowly, but has strong jaws and spits out "lightning balls" from a distance.
 * Baron of Hell: Two of these act as the boss in Knee-Deep in the Dead, resembling large blood red Satyrs. It can hurl streaming balls of green flame or energy and employs a powerful clawing attack at close range. They can take enormous punishment before being slain.
 * Cyberdemon: The massive boss in The Shores of Hell, a monstrous humanoid cyborg as tall as two men that can absorb more damage than any other monster and moves at a relatively rapid rate for its size, pausing only to fire rockets from its mechanical arm at anything foolish enough to oppose it.
 * Spider Mastermind: The cybernetic boss 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 thus also Final Doom) includes the same monsters as Doom in addition to the following monsters:
 * Heavy weapon dude: A tough, corpulent zombie with a darker skin, red armor and carries a chaingun.
 * Revenant: A tall, skeletal demon wearing silver body armor that can launch ballistic or guided missiles, and punch opponents when 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.
 * Arachnotron: Strongly resembles the spiderdemon, but is much smaller, and shoots greenish plasma instead of super-chaingun rounds.
 * Mancubus: A grotesquely bloated humanoid with flamethrowers instead of forearms. It moves slowly, but takes a fair amount of ordinance to bring down.
 * Pain elemental: A large flying head resembling a brown cacodemon with small arms. It attacks by spitting lost souls at its target, and even creates a few more as it dies.
 * Icon of Sin: Though not technically a monster, it does still represent one of the protagonist's opponents. The principal one, to be exact, that must be defeated to win the game.

Cameo enemies:


 * Wolfenstein SS: Populates 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 varients):


 * 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.


 * Malrath - 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 Manchubi class of monsters in Doom RPG.
 * Mancubus - The Mancubes is the 2nd strongest of the three Manchubi 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.
 * Cerbeus - 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 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. The 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 - They were once UAC civilians, now possessed by evil spirits
 * Chainsaw zombie - The Chainsaw Zombie, or "Sawyer" for short, is new to the Doom series as it is the first Doom zombie with a chainsaw.
 * Fat zombie - A Fat Zombie is a Zombie that is obese, but behaves like most other zombies.
 * Flaming zombie - The Flaming Zombie, or "Bernie" for short, is new to the Doom series as it is the first Doom zombie literally set on fire.
 * Morgue zombie - Doom 3's Morgue Zombie looks somewhat similar to the bony zombie but has underwear and is less skinny.
 * Boney zombie - The encounters with hellish Bonies are removed in Doom 3 BFG Edition in both Doom 3 and Resurrection of Evil.
 * Zombie security guard (Z-Sec) - In contrast to the classic former humans, which were previously government Marine soldiers, Z-Secs were originally UAC security guards.
 * Zombie commando - Human Marines transformed into brutal super warriors by the demonically possessed Dr. Betruger.
 * Imp - The Imp in Doom 3 is humanoid in shape, has grey skin with bony scales on its arms and 10 small eyes.
 * Lost soul - The Lost Soul in Doom 3 is a flying demon consisting of a human female face mounted on a flying rocket engine contraption.
 * Demon(Pinky) - This cybernetic demon has no visible eyes, its horns point straight forward instead of out from the side of its head, it walks on all fours in a canine style.
 * Revenant - The Revenant in Doom 3 is a tall skeleton-like demon armed with a pair of shoulder-mounted missile launchers that fire relatively slow-moving homing missiles.
 * Cacodemon - Compared to the original monster, is taupe in color, has a wider mouth, and has multiple green eyes, as well as some longer, thin tentacles hanging from the bottom of its body.
 * Hell knight - It has no visible nose, and its deformed ears resemble a human's, fused to the sides of its head. Its obscure eyes are very small and black, located on the sides of the head just above the mouth.
 * Mancubus - The Mancubus is a very large, fat demon with a fireball launcher for each arm.
 * Arch-vile - It is a large, off-white colored humanoid demon, standing a head taller than a normal human even in its standard semi-crouched pose.

Additionally, the following new monsters are encountered:


 * Cherub - It has the appearance of a human baby with insect-like wings (which produce a characteristic insect buzzing sound when in action) and black sclerae.
 * Tick - The Tick is a small, spider-like enemy in Doom 3 that has similar attack patterns to the Trite.
 * Trite - Trites resemble spiders, being an upside-down, human-like head with several spider-like legs, albeit only six of them.
 * Maggot - Maggots have two heads and two long black tongues (one for each head). Their back is hunched and consists of two large, tumor-like bloody stumps with retracting barbed bones protruding from them.
 * Wraith - Wraiths are limited to melee attacks with their falx-like arms, and run forward to attack the player. They possess a so-called "teleportation" ability, disappearing for a few seconds before reappearing several feet ahead of their previous position.

Boss monsters:


 * Vagary - The demon has the lower half of a giant spider and the upper half of a woman.
 * Guardian of Hell - This crocodilian-like demon stands more than 15 feet tall, just a little over 2.5 times taller than a human soldier.
 * Seeker - The Guardian of Hell is blind due to its age; what remains of its eyes are shallow pits. In order to 'see', It summons smaller creatures called Seekers, as spotters.
 * Sabaoth - Sabaoth is actually Sergeant Kelly after his demonic transformation. His lower half has been replaced with a tank-like vehicle, while his upper half is a twisted body attached to heavy machinery armed with a very sharp claw and a shoulder-mounted BFG.
 * Cyberdemon - It stands roughly 20 feet tall, more than 3 times as tall as a human soldier. While the Cyberdemon overall retains its appearance as a minotaur-like giant.

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 - The Bio-Suit Zombie, normally found in toxic areas where there is no oxygen, wears a yellow hazmat suit.
 * Vulgar - The Vulgar have only two eyes that have an orange glow. They are slightly shorter and have a monkey-like frame instead of human.
 * Forgotten One - Resembles the classic lost soul more than does its namesake.
 * Bruiser - The aptly named Bruiser has a large muscular body in the vein of a hell knight and identical mechanical features of a mancubus, although both creatures' robotic parts look different.

Boss monsters:


 * Hell Hunter
 * Helltime Hunter - He 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 - He has 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 - The Invulnerability Hunter is noticeably larger than a Hell Knight, and has a bulging, extremely muscular body with a blue aura surrounding it.
 * Maledict - The Maledict is the demonic reincarnation of Dr. Malcolm Betruger. The Maledict appears as a mostly skeletal wyvern with a large set of wings, two legs with clawed feet, a long tail and a head similar to a Forgotten One.

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, capable of climbing up walls and leaping over large gaps. Can also charge their fireballs into more powerful versions.
 * Pinky - Covered in thick armour 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 armour 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.
 * Summoners - Essentially renamed Arch-viles; they have similar abilities to their Doom 3 counterparts, but now float, can travel at untouchable speeds, and have a revamped appearance.
 * Cyber-Mancubus - Mancubi with heavier armour, 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.
 * Tentacle - Tentacles can be found on certain levels. When approached, they will emerge from holes in the ground and damage the player.

Fodder

 * Zombie - Returning from previous games, the Zombies behave similarly to the Possessed from Doom (2016) and come in a number of visual variants:
 * Mecha-Zombie - This variant of zombies appear as red eyed skeletal versions of regular zombies but utilises multiple mechanical implants and an inbuilt flamethrower/plasma blaster.
 * Cultist Zombie - It's just a normal zombie with clothes, pale white eyes and no pentagram on their head.
 * 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.


 * Cueball - Similar to the Possessed Engineers from Doom (2016), the Cueball will simply stand in place and will become an explosive missile when damaged.


 * Soldier - The Soldier comes in two variants which resemble the Possessed soldiers from Doom (2016):
 * Soldier (Blaster)
 * Soldier (Shield)
 * 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).
 * Maykr Drone - The only non-boss Maykr enemies in the game, these drones have highly resistant bodies but can be easily dispatched with headshots. When killed with a headshot, they explode into a pile of ammo, similar to Chainsaw kills.

Heavy

 * 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.
 * 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 armour 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.

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