Kongō Gaikokkaku

The Adamantine Exoskeleton is Kagemori Nijiki's ultimate expression of the Jūjin Kekkei Mōra. This perfect synergy of Sennin Transformation and Dead Bone Pulse grants offensive, defensive, and supplementary capabilities. Thus it exemplifies the incomparable marriage of the irresistible force with the immovable object.

Background
Nijiki discovered her father's ultimate technique while interrogating a Root assassin, who'd infiltrated the Land of Whispering bone for the specific purpose terminating her existence. She defeated him in single combat and upon his capture she utilized a combination of fuinjutsu and genjutsu to break and interrogate the perpetrator. Upon doing so she discovered her would-be assassin numbered among those sent to slaughter her parents. In his mind's eye she witnessed firsthand the power of her fathers bloodline and was able to replicate many of his devastating skills, including the Adamantine Exoskeleton.

Execution
To perform this technique Nijiki accelerates her stem cell production to abnormal levels. These stem cells form trillions of osteoblasts funneled through the circulatory system to the capillaries in her skin. In an instant, her pores ooze a puss like substance that shapes itself into a full blown exoskeleton, covering her entire body. The armor soon reaches maximum density, becoming all but impervious to physical harm, yielding an impregnability rumored to be greater than the steel skin of the 3rd Raikage and comparable to the level of Susanoo variants.

Effects
Aside from its impregnability, the armor also allows for instant formation of piercing and cutting weapons. The exoskeleton contains it's own links to the chakra pathway system, leading to enhance chakra manipulation. In this state Nijiki is able to perform techniques denied her in her base form such as: Yasogami Kūgeki and Tomogoroshi no Haikotsu.

Caveats
The Adamantine Exoskeleton remains a rather chakra taxing technique. However, since Kagemori Nijiki possesses tailed beast level chakra, she is capable of maintaining this state indefinitely.