- "Customized machine pistol that is light, compact, and optimal at short range. Possesses a high rate of fire."
— In-game description
The SMG-12 is a fast-firing weapon featuring high vertical and horizontal recoil. The weapon's recoil consistently shifts to the left throughout the 4th to 13th shots, after which it quickly shift to the right and to the left again before the magazine empties. This means that while it thrives in close quarters, it is advisable to fire in shorter, more controlled bursts at medium to long range in order to remain accurate. Unlike the SMG-11, it cannot equip barrel attachments, this is due to its integral suppressor. However, it can equip an Angled Grip.
- Very high rate of fire
- Integral suppressor
- High magazine capacity
- High vertical and horizontal recoil
- Lacks barrel attachments
- The SMG-12 is heavily based on the MasterPiece Arms MPA935SST pistol, while its trigger guard draws inspiration from the MPA930DMG. It features a custom folding wire stock and a KeyMod interface on its integral suppressor.
- Unlike the SMG-11, the folding stock does not close when not in use.
- The reload animation for the SMG-12 has been changed a few times:
- Initially, the reload animation was the exact same as the SMG-11, where the charging handle was depicted as non-reciprocating, as is the case for the real life MPA series of pistols.
- Later the charging handle was depicted as reciprocating, staying locked in the rear when not firing, which is appropriate for an open-bolt firearm.
- When Warden was introduced, his SMG-12 depicted the charging handle as once again non-reciprocating. During a reload, he would lock back the bolt to the rear, and replace the magazine. Curiously, the handle would return to the forward position by itself shortly after a new magazine was loaded. This animation was later used for Dokkaebi and Vigil's SMG-12s.