A Hero Within The Darkness
Itachi Uchiha (うちはイタチ, Uchiha Itachi) was a prodigy of Konohagakure's Uchiha clan. He became an international criminal after murdering his entire clan, sparing only his younger brother, Sasuke. He joined Akatsuki, where he came into frequent conflict with Konoha and its ninja, including Sasuke, who sought to avenge their family. After battling with Sasuke and losing his life to a terminal illness he had been battling prior, it was revealed that Itachi's motivations were more complicated than they seemed and that he only wanted to protect his brother and village, remaining a loyal shinobi of Konohagakure to the very end.
Eventually, at age 13, he was promoted to the rank of Anbu captain. When the Uchiha clan began planning to overthrow Konoha, Itachi was tasked with exploiting his position to spy on the village. Knowing that a coup d'état would only trigger the beginning of another ninja-world war, Itachi became a double agent, feigning loyalty to the Uchiha while secretly passing on information about them to the Third Hokage and Konoha elders. Itachi's best friend and brother-figure, Shisui Uchiha, opposed the coup d'état as well, but after having his right eye stolen by Danzō for its powerful Mangekyō ability, Shisui realised that it was beyond his power to stop the Uchiha clan's impending doom. Meeting Itachi in secret on a cliff overlooking the Naka River, he entrusted his remaining eye to him, requesting that Itachi protect the clan's good name before proceeding to "erase his existence". The grief of losing his closest friend ultimately awakened Itachi's Mangekyō Sharingan, which he soon after used to read more of the secret stone monument.
I'll give you my heart if you give me your hatred, your sadness, your pain..
I'll give you my happiness if you give me your sword and I'll be your destroyer..
I'll give you my soul if you give me your lust for blood and I'll be your assassin..
Give me your tears and I'll b e your angel of death and do as your please..
Give me your fears and I'll be your demon of vengeance killing without hesitation..
Give me your nightmares and I'll be your soul reaper to command as you please..
I'll Be.... Your blade of Vengeance if that is what you wish.