Eight Gates Released Formation

The Eight Gates Released Formation is the state assumed by a user who has opened all Eight Gates.

Overview
To open all Eight Gates, the user must puncture themselves just above the heart. Opening the eighth gate (and all seven preceding it) will cause the user's blood to emanate a flaming aura of red steam from all pores of their body, hair, and eyebrows.

Entering this state uses up all of the body's energy while making the heart pump at maximum power, temporarily gaining powers a hundred times greater than their normal self, far beyond that of the five Kage. This is seen when Might Guy opens all eight gates and fights on par with, and gradually overwhelms Madara Uchiha — the Ten-Tails' jinchūriki at the time — causing Madara to compare his fight with Guy to his fight with Hashirama Senju at the Valley of the End.

Drawback
As with opening any of the other seven gates, opening the eighth will damage the user's body. Unlike the preceding seven, however, releasing all Eight Gates will lead the user to inevitably die because of the damage done to their body.

Under regular circumstances, the effects of opening the eighth gate will cause the user to crumble to ash and subsequently die, having virtually cooked themselves from the inside-out.

Trivia

 * Might Guy survived the fatal repercussions of opening all Eight Gates thanks to Naruto Uzumaki's Yin–Yang Release. However, the damage done to his leg as a result of using Night Guy left him wheelchair-bound for the remainder of his life while forcing him to retire from active duty as a ninja.
 * In Naruto Shippūden the Movie: Bonds, Shinnō claimed that his Body Revival Technique, combined with Dark Chakra, allows him to open all eight gates without any drawbacks.