is demon slayer: kimetsu no yaiba episode 31 filler?

With Enmu’s body now fused with the Mugen Train, the over two hundred passengers have become hostages. As Enmu’s tentacles try to attack the passengers, Tanjiro recognizes the limits of his ability to protect everyone.

In addition to a freshly-awakened Inosuke, Nezuko, Zenitsu, and Rengoku join Tanjiro in an all-out fight to protect the lives of the passengers.