True Tetsujin Technique

The True Tetsujin Technique is an advanced from of the Tetsujin Technique, raising the Kurogane Clan's signature ability to its highest level. While the original Tetsujin Technique enabled its user to empower a specific portion of their body on command, this technique turns the user's entire outer body into an armor of living steel, rendering them virtually impervious to harm. Because of the significant number of immunities of Steel Release techniques, (re: earth, fire, wind, and water), ninjutsu is largely ineffective against this armor as well, and a ninja clad in it can not easily be stopped, merely delayed. The use of this technique during the Warring States Period led to the Kurogane Clan becoming known as.

The technique does have some manner of versatility; Akane Kurogane would use this technique to, in addition to providing armor, extend claws on her hands and feet, giving her taijutsu an increased measure of lethality.

Drawbacks
The True Tetsujin Technique's armor, while highly formidable, is not invincible. Although Steel Release, being a combination of Earth Release and Fire Release provide a unique degree of cover-protection from most other chakra natures, there is nothing to counter Earth's natural weakness to lightning. As such, the armor is easily penetrated by lightning techniques. In addition, the metal shell greatly increases the user's weight, reducing their speed. It also consumes a massive amount of chakra to maintain, rendering it unviable to ninja with less-than-adequate chakra reserves.