Mū

is the of Iwagakure. He has been resurrected by Kabuto Yakushi to fight in the Fourth Great Shinobi War.

Appearance
It appears that the entirety of Mū's body, or at least above his waist, is covered by intricately wrapped bandages, with only his eyes and nose visible. These features are accentuated by a dark colored headband with no distinguishing markings but due to the effects of Summoning: Impure World Resurrection, his eyes now demonstrate distinctive black sclera and white irides.

Abilities
Mū has been observed utilizing some sort of ability that allows him to become completely invisible. 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.

Shinobi World War Arc
Mū, as a former Kage, was resurrected alongside various other notable shinobi by Kabuto Yakushi, in preparation for the Fourth Great Shinobi War.

After the development of these circumstances and the beginning of the conflict, he proceeded to head towards the Fourth Division's present destination. However, upon approaching his adversaries' location concealed from view, he was detected after inadvertently activating 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.