They are often thought of as the bravest, most loyal (and possibly most insane) soldiers found serving under their respective armies. Unlike most other types of infantry, they are not equipped with conventional weaponry. Most fanatics are trained to sabotage vehicles, and are also famous for their leaping knife attacks.
Should they kill the player, they'll stop their tracks to point and laugh or sarcastically shrug their arms. That is until the player respawns; all fanatics scream in terror and get back to work.
Rebel Fanatics: The fanatics used by the Rebel Army. They are capable of various attacks:
- A simple slash of their knife.
- A daring leap slash.
- Throwing Rockets resembling fireworks from their bags. These rockets slowly descend to the floor but can fly higher in the air when the player shoots at it; throwing a grenade makes it fly higher.
- Rolling ball-shaped grenades resembling bowling balls from their bag.
- Laying on the ground and placing mines. These mines are prone to self-detonating and can kill unsuspecting Rebel allies.
Metal Slug: Super Vehicle-001 has Rebels use tactics unique to this game:
- In Mission 1's swamp section, a Rebel can cut off the rope of a dangling bag of boulders.
- Some Rebels in Mission 3 are seen rolling large snowballs down an incline to crush those in their way.
- Starting from Mission 4, if the player is driving the SV-001, some of the fanatics will attempt to jump onto the Slug and will either use a grenade to damage the hull, or use a hammer to remove the Vulcan cannon.
Ptolemaic Fanatics: The fanatics used by the Ptolemaic Army. These come in two groups: scarfed Guerrilla soldiers who work in field operations and gas-masked Special Forces soldiers who work in urban areas. In addition to the weaponry used by the Rebel army, Ptolemaic fanatics are also equipped with throwing knives. They appear in Metal Slug 5.
Future Fanatics: The fanatics used by the Future Rebel Army. Being from the future, their weaponry has been upgraded:
- Instead of a knife, they use a glove that discharges a lethal electric shock.
- Instead of Rockets, the fanatics drop to the ground and release missiles from their bags.
- Instead of Ball Grenades, they use large bouncing bombs called Bound Ammo. The fanatics deploy Bound Ammo by turning around and opening their bags.
- Their antennae produce static when the fanatics run around. The static clusters to produce Laser Bombs that leap off the fanatics' helmets to the ground.
Phantom Fanatics: The fanatics used by the Phantom Squad subdivision of the Rebel Army. Aside from the usual weaponry, some wear helicopter helmets to attack from the air. The subdivision also holds some of the more aggressive soldiers, particularly those who wield machetes with a grin on their faces and can ambush players from above using rope. They appear in Metal Slug: 1st Mission and Metal Slug: 2nd Mission.
- Metal Slug Defense and Metal Slug Attack unit descriptions