Topic summary
Caesar Clown

Extracted from the Wikipedia article List of One Piece characters.
Caesar Clown
Caesar Clown (シーザー・クラウン, Shīzā Kuraun) is a psychopathic former Marine scientist capable of transforming into gas due to the Logia-type Gas-Gas Fruit (ガスガスの実, Gasu Gasu no Mi). He is a former member of MADS and a leading expert on chemical weapons of mass destruction. He works for Donquixote 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 Donquixote Pirates. After his defeat at the hands of Monkey D. Luffy, he is taken to Dressrosa by the Straw Hat Crew and Trafalgar Law as a prisoner to make a hostage swap with Doflamingo. Despite his antagonistic relationship with the Straw Hats, he cooperates with Chopper in medicine production and assists in improving his Rumble Balls. After his escape, he cooperates with former MADS colleague Vinsmoke Judge to form NEO MADS in order to surpass Vegapunk only to be dismayed by the news of Vegapunk's death on Egghead.