The Zorg Mercenary is a bipedal, skinless lizard-like creature. Its people, the Zorg, managed to create a large interstellar empire. After conquering enough planets, they decided to take a very long break by sunbathing from 10am to 4pm. The amount of sunbathing eventually caused their skin to fall off. After their disastrous vacation, Mental hired huge numbers of them and imported them from an unknown universe to act as disposable grunts. They now attempt to stop Serious Sam.
Mercenaries are the main lightweight ground troops in the second encounter, largely replacing beheaded rocketeers. They can be encountered in groups of any size and usually a few Zorg Commanders are found with them.
The mercenary's attacks resemble those of Beheaded Rocketeers, with the differences being the Mercenary's gun firing two blasts in quick succession, with twice as much damage and faster projectile speed as the Rocketeer's projectiles. Generally, if one projectile hits a target, the other will almost always as well because of how quickly they are fired. They have no melee attack, even in Serious Sam HD.
- Mercenary projectiles are easy to dodge; the player can either strafe past them or jump over them if they don't have enough room to strafe past them.
- Lone or small groups of Zorg Mercenaries can be defeated with either the Schofield .45, 12 Gauge Pump-Action Shotgun or M1A2 Thompson.
- Large groups of Zorg Mercenaries can easily be cut down with the M1A2 Thompson or XOP Flamethrower in a matter of seconds. If Mercenaries are clustered together, one rocket or grenade can take out the entire cluster and significantly harm any Mercenaries near it.
- Mercenaries are a minor nuisance when mixed with other enemies. They should not be a priority target when taking out a group of enemies. With rapid-fire weapon, lining up zorgs with more dangerous enemies mean that they go down as well.
- In the Second Encounter, the player can select the Mercenary as their multiplayer model under the name Skinless Stan.