is one piece episode 724 filler?

Luffy is sent flying into the palace rooftop after clashing with Doflamingo, and Trebol catches him in a large pile of mucus, which immobilizes the pirate. Trebol tells Luffy that he will be dealt with later, but now it is time for Doflamingo to kill Law without opposition.

Luffy desperately tries to fight his way out of the mucus, and attacks Trebol using Armament Haki. However, despite punching a hole through Trebol, the executive only laughs.

Luffy expresses his confusion, as he thought Trebol was a Logia, but Trebol questions that assumption.