And he developed many kinds of Ninjutsu.
Shisui also taught those Ninjutsu to Itachi,
After Shisui died, those crows were raised by Itachi
During the Fourth Great Ninja War,
Itachi Uchiha's Mangekyo Sharingan met Naruto,
Thus it activated the crow which is buried in Naruto with Shisui's eye (Sharingan),
Shisui's Sharingan released Kotoamatsukami towards Itachi to protect Konoha,
And freed Itach from Kabuto Yakushi's control.