The K-O3 Coupled Armored Vehicle is a trio of a transport supply vehicle, exclusive to Metal Slug Attack. It first made its debut on the game's event titled 'Try Line 3rd', where the boss can also become a playable unit.
Coupled armored vehicle developed independently by the Rebel Army. Fitted with special batteries in order to transport supplies safely to the battlefront. Damaged cars can be detached, and the vehicles can operate in one-car formation as well.
- ~Metal Slug Attack in-game description.
In Metal Slug Attack's event, this boss is fought at the last stage. The boss will attack the player's units with its cannon via coupled battery, its attacks are ordered by a Rebel Infantry which can be seen on the top of the boss.
The special attack of the boss will also fire 2 yet slow-moving cannon shot with its frontal battery (4 with 4). The projectiles combine together to form a bigger one before it collides on the ground to create a bigger explosion.
This stage is practically annoying, as the boss can travel fast towards the frontlines and destroy the player's base with ease. Without deploying cheap units below 100 AP, the boss can wreak havoc and snipe the base with ease via its special attack.
In-battle as a playable unit, once the first caboose has accumulated sufficient damage, the front car will perform a Metal Slug Attack-styled suicide attack charge. This however only happens when 3 is unlocked. The long range attack will also be modified in order to adjust for the remaining cars, however the special attack still remains the same.
- Its design resembles the Rebel Train from Metal Slug: 1st Mission.
- In the game's files, it is known as "Renketu", a Japanese translation for 'Linking'.