Naruto Episode 72 -

Orochimaru reveals the true purpose of his research: Immortality . He peels away his face to show the stolen body of a girl, explaining his Living Corpse Reincarnation technique. He openly admits his goal is to take Sasuke’s body next.

This episode features a significant flashback of Team Minato (Minato, Kakashi, Rin, and Obito). Naruto Episode 72

Regretting his past failure to stop Orochimaru, Hiruzen prepares the Dead Demon Consuming Seal , a forbidden technique developed by the Fourth Hokage that requires the user’s life as a sacrifice. Orochimaru reveals the true purpose of his research: