I believe "Ninner" is a distant relative of everyone's favorite alien Mork (of Mork and Mindy). Or - it could be a derivative of the derogatory term that Dr. Smith used to often refer to his robotic friend - "You Ninny" Since the OP stated "Villains beware!" I tend to believe that that he / she has simply made a toon (probably a Quantum?) of his / her favorite long lost space Alien Mork.
sounds like a hero out to rob villains of nourishment. -the ninner swoops in from nowhere making sure no villain has a pleasant dinner- "muahaha villains no dinner for u. you shall have ninner" thats what i thought of -shrug-
I'm personally nominating Ninner for the Titanic Trenton School of Excellency. He is fast becoming one of my favorite forum posters. If I see this player in game, he will get a crisp salute from me.