Steel Release: Impervious Armour
Debut
Movie	Naruto Shippūden 3: Inheritors of the Will of Fire
Appears in	Movie only
Data
Classification	Kekkei Genkai, Ninjutsu
Type	Steel Release
Class	Defensive
Users Hiruko

This technique allows the user to turn their body into black steel, making that part invulnerable. Hiruko states that blades do not affect him at all due to this ability. The portion converted into black steel is similar in appearance to Kakuzu's Earth Spear technique. Hiruko uses it to counter Sai's tantō, causing it to snap clean in half on impact.