Revived by the technique of the Impure World, Muu maintained an icy calm and did not show the slightest surprise at his own resurrection. He remained impeccably polite, patiently explaining to the other Kage the circumstances of their summoning and addressing the Second Mizukage by a respectful title, despite their old enmity. His main concern remained Iwagakure, and even as a puppet he reminded Ōnoki that after the war he must immediately seize all advantages for his home village. When the shinobi alliance protested such cynicism, Muu was not at all embarrassed, considering his position to be the only correct one. In battle, he acted calculatingly and without hesitation, instantly analyzing the situation and anticipating the enemy's moves. He easily recognized the method by which Gaara detected his invisibility and immediately ordered the other Kage to be summoned. Despite being under Kabuto's control, Muu tried to help the alliance: he warned his former student that he had split his body in two, although his voice did not reach its target. His consciousness was sometimes completely suppressed, and then he became an obedient conduit for negotiations between Kabuto and Madara. But as soon as the technique was canceled and his personality returned, Muu became himself again — composed and businesslike. Even before his final dissolution, he showed no fear, only asking to tell Ōnoki that he must protect the future of the alliance. His will to serve Iwagakure did not weaken even after death, and his cold-bloodedness made him one of the most dangerous warriors of the Edo Tensei.
