Earth Release: Earth Spear

The user flows chakra through all parts of their body causing it to become noticeably darker, which increases their defensive power to its utmost limits by making the skin as hard as steel (databook). Furthermore, the destructive power of physical attacks is increased, making this a great all-purpose technique. The amount of techniques that can break through the areas hardened by the Earth Spear are close to zero, excluding its undeniable weak point: Lightning Release ninjutsu. Kakuzu used this technique through the use of his earth-element mask.

Kakuzu demonstrated the ability to use this to cover himself partially (i.e. his hand and lower arm, and the side of his head) without using handsigns, which gave him a significant tactical advantage against ambushes.

Trivia

 * Like the rest of Kakuzu's techniques, the name of this technique comes from the legendary mecha anime . The name Domu was taken from the Gundam MS-09 . The name was given kanji to create the name of this technique.
 * This technique's attribute of darkening of skin colour as a result of hardening is similar to Hiruko's Steel Release technique.