is one piece episode 839 filler?

With the Big Mom Pirates back on the move and surrounding him and his allies, Bege activates Rook In Voller Größe: Big Father, turning his entire body into a fortress and growing massive in size. He tells his crewmates and allies to get inside him, and the Fire Tank Pirates shoot at the Big Mom Pirates to keep them at bay.

As Nami, Chopper, and Carrot run toward Bege, they are knocked away by Caesar who is rocketing toward safety, causing them to get stuck in some cake. Caesar's progression is halted when Katakuri grabs Brûlée, who is still kept in Caesar's backpack, with a mochi arm.