Susanoo is the ultimate ability available to those who have awakened the Mangekyo Sharingan and mastered its power in both eyes, passed down through the Uchiha clan from generation to generation. It materializes a giant humanoid guardian from the user's chakra, which surrounds its master and acts as an extension of his will — attacking, defending, and using techniques. Susanoo develops in stages: first, a skeletal structure appears, then muscles and skin form, a full torso takes shape, and at higher stages armor, legs, and finally a colossal Complete Susanoo emerge, reaching the size of a tailed beast and gaining wings for flight.
Activating the technique requires enormous chakra expenditure and causes a sensation of pain in every cell of the body, intensifying as it transitions to more complete forms. Susanoo can selectively allow attacks from the user and their allies to pass through it, but it does not regenerate when damaged — recovery is only possible by dispersing and reforming it or by advancing to the next stage. Its physical defense is nearly absolute, but the technique does not protect against attacks that directly affect the senses, such as sound waves or genjutsu. At stages without manifested legs, the lower part of the body remains vulnerable, where one can reach under Susanoo, for example, from underground, and an opponent who manages to grab the user can pull them out from under the protection.
Each Mangekyo wielder receives a unique incarnation in terms of color, appearance, and armament. Itachi Uchiha wielded the Totsuka Blade, which seals everything it pierces, and the Yata Mirror, which changes its properties to reflect any attack. Sasuke Uchiha is armed with a bow and arrows, whose properties can be enhanced with black flames or lightning; his Complete Susanoo gains a demonic helmet with a long tengu nose. Madara Uchiha used a two-faced Susanoo with four arms and curved blades that could be thrown at the enemy. Madara's Complete Susanoo could cleave mountain peaks from a distance with a single katana. It is also known that Indra Otsutsuki, Kakashi Hatake, and Hagoromo Otsutsuki wielded this power, with Kakashi's Susanoo bearing scars mirroring those of its user.
