is one piece episode 728 filler?

Encouraged by Riku Doldo III's speech and by Luffy overpowering Doflamingo, the citizens of Dressrosa run away from the shrinking Birdcage in hopes of protecting their lives. Meanwhile, Doflamingo continues turning building into string and sending them after Luffy.

The pirate struggles to navigate them and get near Doflamingo, who is nursing his internal wounds and intent on finishing their battle. Luffy screams Doflamingo's name, and the Shichibukai nearly wraps him up in a mass of string, sending him bouncing uncontrollably across the street.