is bleach: thousand-year blood war (bleach: sennen kessen-hen) episode 7 filler?

A thousand years in the past, with the Seireitei heavily damaged and burning in several areas, Yhwach leads his army of Quincy toward Genryūsai Shigekuni Yamamoto and the original captains of the Gotei 13, who begin slaughtering the assembled Quincy with their respective Zanpakutō. When only Yhwach is left, Yamamoto approaches the former with his Bankai, Zanka no Tachi, burning the mountain of dead and dying Quincy that they are standing on.