The Samurai (1962)

Butterfly Spy (8x5)

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The Phantom ninja take a doctor to treat Hagenbō and kill him partly so he won't reveal the location of the House of Night and partly as bait to lure out Shintarō and Tonbei by leaving the body in a temple. While they are out, the Phantom ninja kidnap Shūsaku and threaten to kill him if either Shintarō or Tonbei leave the Sainenji (where lives). Chidori makes sure they stay bottled up while the Phantom set about killing the others in the "book of death" by spying on them with her "echo butterfly" technique. However, Tonbei destroys the butterfly and they rush out to find Hagenbō with Shūsaku . He almost kills with his "human steel" technique (and would have if he'd had both arms, Shintarō admits). Hagenbō is killed.