"Who is This?" (これは誰だ?, Kore wa Dare da?) is chapter 583 of the original Naruto manga.
Summary
Kabuto Yakushi flashes back to the time when the orphanage aided several Konohagakure shinobi by healing them. Asked by Orochimaru, who thought his skills were impressive whether or not he had thought of being a shinobi, to which Kabuto declines. Nonō is later approached by Danzō Shimura, Orochimaru and another unknown shinobi, who blackmail her into undertaking an intelligence gathering mission based on the intel they had received that Iwagakure was planning a big attack. Taking Kabuto along with them to replace a dead Root member, the young man was sent on several spy mission in different hidden villages inclusive of the Five Great Shinobi Countries. On a mission in Iwagakure, his cover was blown and as he attempted to escape he was confronted by an Iwa-nin. Kabuto attacked the ninja with his chakra scalpel severely wounding the enemy. This person turned out to be Nonō much to Kabuto's shock as he tried to heal her. She however did not remember him, which devastated Kabuto who ran off and left her as Kitsuchi and another Iwa-nin approached them. Devastated that she did not remember him and wondering who he was, Kabuto is once again approached by Orochimaru who states that he had become quite the shinobi.