is one piece episode 643 filler?

During the confrontation between Law, Doflamingo and Issho on Green Bit, Caesar Clown yells to "Joker" to finish off Law already. Law tells Doflamingo that he broke his promise and they were going to have to start their deal from scratch again.

However, Doflamingo laughs at this and tells Law to leave his subordinate Caesar alone. At that moment, Issho and his men realize that Law’s hostage is none other than Caesar Clown, the criminal scientist behind the poison gas incident.

However, Issho says that because he is the subordinate of a Shichibukai, he is exempt of his crimes.