When a Sub-weapon Carrier appears, shoot at it and it will drop a Sub-weapon Unit. Collect it to equip MUSHA with a Special Weapon.

With the exception of the DEFENSIVE DETONATOR, press ( for the Classic Controller) to fire your Special Weapons. If you catch a Sub-weapon Unit of the same kind you currently have equipped, the Special Weapon Level rises. Catch a different kind, and the Special Weapon will simply change (but retains the current Special Weapon Level). The Special Weapons can take a hit from the enemies’ shots and will be lost, but you will not lose the Special Weapon Level. However, if you lose a MUSHA, you will lose both the Special Weapon and your Special Weapon Level.