The Pirates are minor enemies in the fifth mission of Metal Slug 4. Despite the fact that their behavior and sprites were recycled from the Arabians (except the swordsman that they won't drop meat upon their death like the Arabian fighter), they have no relation to them whatsoever.
In the events of Metal Slug 4 they were able to board and take over a merchant vessel. It is suggested that the cargo ship belonged to the Regular Army, explaining the presence of Rebels and the PF Squad aboard the ship.
Grunt: This is the most common type of pirate. They use cutlasses to attack, occasionally throwing them at the player. In the second part of the mission they appear in Hammer-Yangs.
Swordsman: This variety of pirate is armed with a light sword. They attack by running back and forth, slashing at the player if they get in range.
Pistol Swordsman: These swordsmen not only have the standard light sword, but are also armed with a pistol. They are seen only a few times.
- Since they have "Traditional" pirate swords, turbans, flintlock pistols and skull emblems on their shirts it is safe to assume they are based off of "Traditional" European-Caribbean pirates.
- In Metal Slug Defense's description of the Pirates, It was claimed as they are working for the Amadeus Syndicate.
- However, the Pirates are classified as the Independent/Monster faction, as there is no Amadeus Syndicate faction in Metal Slug Defense.
|Human||Rebel Infantry | Arabian Infantry | Samurai Infantry | Pirates | Scientists | Ptolemaic Infantry | Natives | Hunters | Future Rebels|
|Undead||Mummies (Mummy Generator) | Dog Mummy | Mutated Soldiers | Zombies | Tar Man | Clones|
|Mutant||Bat | Chowmein-Conga | Ohumein-Conga | Enormous Moray | Jellyfish | Flying Killer | Man Eater | Huge Locust | Sasquatch | Maggot | Big Snail | Giant Caterpillar | Squid | Huge Ivy|
|Alien||Monoeye | Ring Laser Mecha | Hopper Mecha | Mars Mecha | Mars People | Big Eye | UFO | Mini-UFO | Invader Squad | Winged Invader | Flying Parasite | Hunter Walker | Hunter Lord | Scavenger | Crab-Tank | Vanguard | Smasher | Invader UFO | Indestructible UFO | Flying Core|