Again, Phalanx is a female. If “the masked prophet” is just a play on words to make us think it’s Prophet, then my next guess would go to Serial. Though Prophet does give us a clue as to what’s coming next after you beat 14-10.
Serial not only wears a mask, but he also wasn’t in any of the enemy teams for the Gun-der Dome. We know that Serial holds a grudge against the person/s that caused the heronium explosion that took both is arms. Sounds like motive for an evil plan to me. We also know that he was cryogenically frozen, before he was repaired my 4-CEP. With that being said, we don’t know when he went into stasis. It could’ve been a week before the procedure, or it could’ve been years. There is much mystery in Serial’s past, that we have yet to explore.