モンキー・D・ルフィ
is a psychopathic former navy scientist capable of transforming into gas due to the Logia type . He is a former colleague of Dr. Vegapunk and a leading expert on chemical weapons of mass destruction. He works for Don Quixote Doflamingo creating artificial Devil Fruits called SMILEs, and using kidnapped children in Punk Hazard for his experiments. He is also a direct subordinate of the Don Quixote Pirates. After his defeat at the hands of Monkey D. Luffy, he is taken to Dressrosa by the Straw Hat Pirates and Trafalgar Law as a prisoner to make a hostage swap with Doflamingo.