The zombieman (also known as former human in the game manuals, and sometimes referred to colloquially by the Doom community as a trooper) is the least powerful type of opponent in the game and is a local person which has been turned into a zombie during the invasion from hell. The monster appears as a man in a bloodied tan uniform and body armor, carrying a rifle. His hair has an unusual greenish tinge, perhaps stained with green slime or caused by a problem in converting a light hair color into the game palette.
The Doom instruction manual says: Just a few days ago, you were probably swapping war stories with one of these guys. Now it's time to swap some lead upside their head.
 Combat characteristics
The zombieman will make one of three different sounds when alerted: it will either make an animalistic roar or utter two inarticulate chatter sounds. All three zombie types make the same sounds when they spot the player. The zombieman is armed with a rifle that fires bullets that are slightly less damaging than the player's bullets. When the zombie attacks, it aims its rifle at the player for 10 tics and fires a single pellet. The zombieman's weapon has a wide dispersal (standard deviation around 9°, to a maximum of ±22°), and will most likely miss at medium to long ranges. After firing, the monster moves again.
The zombieman is generally considered the least dangerous enemy in the game; no other monster (excepting the Commander Keen) has a lower movement rate, hit point total, or average damage per attack. When killed, the zombieman falls hard on its back with various bits of blood and flesh blown off its form, dropping an ammo clip containing 5 bullets (or 10 on I'm too young to die and Nightmare!); if he subsequently respawns or is resurrected, the zombie will drop another clip each time he is killed again. He can also be gibbed if attacked with powerful weaponry, such as a rocket launcher.
 Tactical analysis
Unless in poor health, an armed player should never need to back down from a single zombieman, although large groups can slowly drain the player's health during the time it takes to kill them all (as in Evilution MAP09). The dispersal of the shots from its rifle means that it is barely a threat at medium to long ranges. In an emergency, or when conserving bullets during a Tyson run, the fist is effective in the short term if the player's footwork is good (two blows will usually knock one down, while a single berserk attack will certainly finish it, often gibbing it). As they are extremely weak and easily disposed of, using heavier weapons against them is considered a waste.
The zombieman's low rate of fire and damage capability make it a rather weak contributor to monster-monster battles. Attrition among a crowd of zombiemen is generally slow, and distraction of larger monsters minimal.
In most stock levels, many of the enemies in the first few rooms are zombies. Unless the player's primary goal is speed, the zombiemen's dropped clips can be a valuable early source of ammunition.
 Inspiration and development
An early version of the zombieman appears in the IWAD file of Doom 0.4, although the sprite (POSSA) does not appear in the game. The sprite is almost identical to the Doomguy; it is slightly lighter in color, and has crudely drawn square red eyes (to show that it is possessed). The only frame is a full frontal view, with no rotations. In Doom 0.5, however, the sprite is virtually identical to the finished version.
- The zombieman has the type name MT_POSSESSED in the Doom source code, and the sprite prefix POSS, while the analogous MT_TROOP and TROO are given to the Imp. The zombies were called "demon-possessed humans" (or simply "possessed humans") in the Doom Bible (section 7.2), being "possessed in their sleep".
- With only 20 hit points, the zombieman can be gibbed with the berserk fist, rocket launcher, plasma rifle, BFG9000, exploding barrel, Demon bites, Cacodemon ranged and melee attacks, Hell Knight/Baron of Hell clawing and ranged attacks, Revenant rockets and Arch-Vile fire attacks. This is more than any other monster in the game.
|Shots needed to kill1,2||Mean|| Standard|
health, no armor)
health, security armor)
health, combat armor)
|Baron of Hell||117.61||17.02||100||159|
- This table assumes that all calls to P_Random for damage, pain chance, blood splats, and bullet dispersal are consecutive. In real play, this is never the case: counterattacks and AI pathfinding must be handled, and of course the map may contain additional moving monsters and other randomized phenomena (such as flickering lights). Any resulting errors are probably toward the single-shot average, as they introduce noise into the correlation between the indices of "consecutive" calls.
- The target must be close enough to compensate for the monster's inaccurate aim.
- Assumes that direct hits are possible, which does not occur in any stock map.
 Appearance statistics
In classic Doom, the zombieman is first encountered on these maps:
The IWADs contain the following numbers of zombiemen:
|Game||ITYTD and HNTR||HMP||UV and NM|
 Other games
 Doom 3
- See Z-Sec.
 PlayStation Doom
In PlayStation Doom, their gunshot damage is increased somewhat, up to a maximum damage of roughly 21. The manual also lists the name of this enemy type as "Former Soldier", as opposed to "Former Human" as in the PC versions' manuals (or "Zombieman" as in the enemy cast at the end of the game).
 Doom 64
In Doom 64, they use a visual appearance that is similar to the vanilla Doom looks, but instead their rifles look more like shotguns and their suits are colored blue-grey. They first appear in MAP01: Staging Area. Also, like in PlayStation Doom, their gunshots deal somewhat more damage than in previous versions (up to about 21 damage).
 Doom RPG
In Doom RPG, the zombieman appears as the "zombie" monster class. There are three different forms, identified by color:
- Zombie private (brown)
- Zombie lieutenant (blue)
- Zombie captain (normal colors)
They are weak against axe attacks.
- In Doom II for the Game Boy Advance, a red blood splatter, half-way covered in green, appears in the zombieman's death animation.
 See also
|Monsters from Doom and Doom II|
|Monsters from Doom 64|
|Monsters from the Sony PlayStation version of Doom|