Zombieman

The Trooper (sometimes known as Zombieman) is a former human who carries an assault rifle. Zombiemen are one of the first monsters encountered when playing Doom, and are the weakest standard monster type. When a Zombieman is killed, he drops a clip of bullets. However, clips dropped by Zombiemen contain fewer bullets (5) than standard clips (10).

Internally the Doom source code gives the Trooper the type name MT_POSSESSED. The sprites for the trooper have the prefix POSS.

While this enemy is commonly referred to as the "trooper", internally the name MT_TROOP (and the sprite prefix TROO) is given to the Imp. This is because the Imp was referred to as the "Demon Trooper" in the Doom Bible.

Appearance statistics
The IWADs contain the following numbers of Troopers: