is one piece episode 525 filler?

The episode opens with the Monster Trio (Luffy, Zoro and Sanji) facing the Kraken. The trio each reveal some result of their intensive training these past two years.

Sanji showing his Blue Walk and a new kick, Diable Jambe: Bien Cuit. Zoro cuts the kraken with his new Three Sword Style technique, Ogi: Rokudo no Tsuji, before Luffy finishes him off with a haki-imbued Gomu Gomu no Elephant Gun.

After the Kraken is defeated, from somewhere inside the Kraken, a big shark wearing a t-shirt appears and thanks them before going to the deep sea.