"An Existence of Falsehoods…!!" (偽りの存在…!!, Itsuwari no Sonzai…!!) is chapter 507 of the original Naruto manga.
Summary
Guy defeats Kisame, who, while unconscious, is restrained by Yamato's Wood Release, so Aoba can gather information from Kisame's past. In the past, when still a shinobi of Kirigakure Kisame was a bodyguard for Cypher Division, but he killed his comrades when danger of secret codes' leak appeard. Later, he killed his superior, who betrayed the village, and took his sword. Then, the Fourth Mizukage approached. Speaking with him, Kisame described his life as one big lie. He then spotted a person controlling the Mizukage. The person promised to release him from lies and introduced himself as Madara Uchiha. Back in present times Kisame bites his tongue and releases himself from stocks.