is bleach: thousand-year blood war (bleach: sennen kessen-hen) episode 4 filler?

In the Seireitei, technicians at the Shinigami Research and Development Institute frantically monitor the appearance of sixteen powerful Quincy within massive Reishi crosses who have bypassed the Shakonmaku and killed hundreds of Shinigami, including 3rd Division Lieutenant Izuru Kira, 3rd Seat Rikū Togakushi, 5th Seat Taketsuna Gori, and 6th Seat Asuka Katakura. Incredulous at the invaders having slain over 1,000 Shinigami in the first seven minutes, 12th Division 3rd Seat Akon asserts that the Gotei 13 cannot possibly win.