Forbidden Secret Technique: Dead Demon Consuming Seal!

is episode 73 of the original Naruto anime.

Synopsis
As the battles across Konoha rage on, the Third Hokage's clones use the Dead Demon Consuming Seal to seal away the souls of the First Hokage and Second Hokage. Turning his attention to Orochimaru, the Third begins to seal his soul as well, though is stopped as Orochimaru's Kusanagi stabs him in the back. Staying alive through sheer will alone, the Hokage reveals that the Dead Demon Consuming Seal is a self-sacrificial technique and that he would die anyway. Meanwhile, Sasuke again catches up with Gaara, and Kankurō prepares to hold Sasuke off while Gaara escapes with his sister. Before they can begin, Shino Aburame arrives to fight Kankurō, allowing Sasuke to proceed.