Earth Release: Earth Spear

With his earth-element mask, Kakuzu can harden his skin to steel-like quality, protecting him from most attacks. Apparently, this technique also enhances his strength, to the point of knocking down a giant iron door protected with a powerful sealing technique with just one punch. It can, however, be pierced by a powerful-enough lightning-based ability, as seen when Kakashi pierced through it with Lightning Cutter. While the technique is active, Kakuzu's skin changes to a much darker, almost black color.

Trivia

 * Like the rest of Kakuzu's techniques, the name of this techniques 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.