is one piece episode 684 filler?

Luffy, Zoro, and Law land in front of the Corrida Colosseum, and as Zoro and Law reflect on how strong Pica is, Cavendish suddenly appears. As Zoro prepares to draw his sword, Cavendish recognizes Law and attacks him because he is one of the Eleven Supernovas, which stole his fame.

Luffy stops Cavendish, saying that Law is his friend, which Law loudly denies. Luffy asks Cavendish if he still hates him, to which Cavendish replies no due to Usopp rescuing him from being a toy.