Secrets of the Reanimation Jutsu Naruto: Shippûden : Season 13 Episode 4

Eight Tails tells Naruto about the limits of Tailed Beast chakra mode and Bee wants to train Naruto in how to use the Tailed Beast Bomb. At the outskirts of Mountain Graveyard, Kabuto demonstrates the Reanimation Jutsu and Tobi releases Fu and Torune as demonstration subjects. Tobi kills Torune and Kabuto extracts Torune's blood which serves as a personal identification and soul retrieval. Kabuto links the jutsu on the incapacitated Fu and transforms into an undead Torune. Kabuto also explains that he cannot summon the previous Hokages because their souls were now sealed by the Reaper Death Seal. Meanwhile, Ao detects a large number of White Zetsus moving underground. Kitsuchi and Kurotsuchi use the Erupt jutsu to spit the White Zetsus out from the ground.