Shisui Uchia

Was one of the most talented of the Uchiha clan. Shisui was the best friend of Itachi Uchiha; in fact, Itachi thought of him as an older brother. However, when Itachi began to act oddly, Shisui was instructed by the Konoha Military Police to keep tabs on him. Soon afterwards Shisui was found drowned in a river. Although it appeared to be a suicide, the police suspected Itachi had murdered him and used his Sharingan to fake a suicide note. Itachi later confirmed this.
At some point in the past, Shisui fought with Ao. Ao retains an acute memory of Shisui's chakra and ability to control others with his Sharingan. Because of this, he recognizes that Shisui's right arm and eye were transplanted into Danzo.
It is also rumored that he was Itachi's 'lover'

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