Mū

is the of Iwagakure.

Appearance
It appears that the entirety of Mū's body is covered by intricately wrapped bandages, with only his eyes and nose visible, giving him an overall mummy-like appearance. These features are accentuated by a dark colored headband with no distinguishing markings. Due to the effects of Summoning: Impure World Resurrection, he has black sclera and white irides.

Abilities
Mū has been observed utilizing some sort of ability that allows him to become perfectly camouflaged with the surrounding environment, in a similar manner to techniques demonstrated by other Iwagakure shinobi. It is hinted by statements that he himself has made, that detecting not only his movements but also his presence is no easy task and something worthy of praise.

He also appears to be both extremely knowledgable and analytical, being able to discern the exact method used to locate his position almost immediately after detection, seemingly without any prior information concerning the technique in question.

Shinobi World War Arc
Mū, as a former Kage, is resurrected alongside various other notable shinobi by Kabuto Yakushi, in preparation for the Fourth Great Shinobi War. When the Kage are mobilized, Mū is sent in the direction of the Fourth Division. As he approaches their location invisibly he is detected by contact-sensitive Sensor Sand, something which he commended his opponents for achieving.

Trivia

 * can mean nothingness or non-existence; possibly alluding to his ability to become invisible.
 * His appearance and the technique he uses may be referring to the main character of "The Invisible Man" novel.