|Steel Release: Impervious Armour|
|Movie||Naruto Shippūden the Movie: The Will of Fire|
|Classification||Kekkei Genkai, Ninjutsu, Chakra Flow|
This technique allows the user to turn their body into jet-black steel. Hiruko states that blades do not affect him at all due to this ability, which is demonstrated when Sai's tantō snapped clean in half on impact.
- The portion converted into jet-black steel is similar in appearance and functionality to Kakuzu's Earth Spear technique, though Hiruko did not show the offensive usage.