Itachi has the greatest ninja resume in the narutoverse.
-2 paneled Orochimaru, hokage contender with Minato, in his preteens - 11 years of age
-demolished deidara, a kage level responsible for capturing gaara - kazakage alive while still handicapping himself(not enough clay, etc etc)
- Took out the strongest clan of Konoha and possible the narutoverse with Madara.
- Tired out and bested Kakashi while staying at the same spot ( in 2 moves)- all the while only exchanging basic ninja techniques ... ninjutsu kunai etc.
- Figured out how to transfer doujutsu techniques to Sasuke
- has handseal speed faster than a matured sharingan can detect
- has speed on par with Gai and LEE ( no one else has 5/5 in speed)
- 5/5 in ninjutsu
- Hailed as the greastest student to graduate from the academy
- Kisame called him the #1 of Konoha
- Madara feared him
- Genjutsu God
- has 5/5 in seal knowledge
- has tsukyomi - god of moon, strongest genjutsu said by zetsu who witnessed the pain fight
- has amaterasu - god of sun, strongest ninjutsu said by zetsu
- has susanoo - god , by databook the only attack that has no weaknesses which has totsuka and yatas mirror which are the
absolute or perfect offense and defense
- beyond all this he has intelligence unlike any other.