"paisen" is a silly way of saying "senpai" (just switch the syllables). The artist is having Mash talk like a ditz. The artist then says Mash's Servant will turn out to be Mash Rene Figaro (The Japanese name for Sabin from Final Fantasy 6), with some joke censoring. The command code is for Sabin's strongest Blitz attack, Phantom Rush. Obviously none of this is serious.