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 Era of Warring States led to the Kurogane Clan becoming known as .