The ASSASSIN (or A Sir Seeker Annihilator Secretly a SIr look alike Nstuff)
It was originaly made as a weapon to be used as an assasin (as the name implies). It can use a holographic deveice to look like any other SIR unit. Tallest Miyuki did not allow this model to be mass-produced, as she thought it was much too dangerous to be put out with Invaders. Several Prototypes were in the making when Plazatrax's lab exploded.
ASSASSINs are adept at many different weapons.