Shinnō

Shinnō was an elderly man with long grey hair that flows out at the back, and muttonchops connected to his beard of the same colour. His eyebrows were thick and of a darker grey, but neatly trimmed. He also had yellow eyes with dark bags around them, and tear troughs under them, giving a somewhat stern look, similar to Itachi and Fugaku Uchiha. In his false persona, his eyes would have a kind and generous look, but once he revealed his true colours, the kindness was replaced with an arrogant and sadistic look. He wore a black shirt with a white gi with brown and blue edges over it, and further a sleeveless red jacket with gold sidings over that, and simple blue pants. He also originally wore a dark red bandanna, which he gave to Amaru before his presumed death. After using the Body Revival Technique in combination with Dark Chakra to increase his strength, Shinnō underwent a great physical change in his body: his hair and beard grew wild and much longer, as well as blackening in colour. His eyebrows became black and wildly thicker. He grew much taller and his muscles greatly expanded, which caused his clothes on his upper body to burst, leaving him bare-chested, with only shreds of the sleeve around his wrists. All this made him look younger and much more physically fit. The creases under his eyes and the dark bags around them also seem to have disappeared. However, after being struck by Sasuke in his tenketsu and causing a backlash in his attempt to use Dark Chakra, Shinnō became a heavily emaciated old man, with his hair turning grey again and falling out, leaving him beardless, no eyebrows, and bald on top, with only wisps of hair at his side, and stubble in where his eyebrows and beard used to be. The creases under his eyes also returned.

In the past, Shinnō taught Orochimaru several forbidden Regeneration Techniques. Thirteen years before the start of the series, Shinnō came to one of the villages in the Land of Fire, claiming to be a former shinobi who turned away from the path of battle to help save lives. In truth, he is an agent from the Land of the Sky, seeking for the scroll to unlock the powers of the Zero-Tails in order for his own country to gain immense power for world domination. Some years after entering the village, an orphaned girl named Amaru fell terribly ill. While the villagers avoided her for the fear of being infected, Shinnō went straight to her house and saved her life, after hours of nonstop surgical operation. He was then welcomed as a celebrated member of the village, and accepted Amaru's request to take her in as an apprentice in the medical arts. Under this cover of a benevolent doctor, however, Shinnō plotted to have the Zero-Tails feed on the villagers' negative emotions over many years time, in order to gather up large quantities of Dark Chakra.