Itachi was a young kid blessed with intelligence and power. According to third hokage at the age of seven he thinks as the hokage and further more itachi was an uchiha. He passe the graduation exam so early. After that his brother was born sasuke uchiha. He always take care of his brother. After the nine tails attack on village uchiha were stricter, so the leader of uchiha clan fugaku uchiha (father of itachi and sasuke) planned for a coup e dat, to stop this itachi friend shisui uchiha tried to put the clan under his special genjutsu but was stopped by danzo. Danzo took one of his eye, he was going to get another eye but was res ued by itachi. He gave one of his eye to itachi and died. After this to stop uchiha clan danzo ordered itachi to kill all his clan. Itachi accepted this mission and at the night he and the other masked guy with sharingan killed all the clan leaving only one survivor. The only survivor was his brother
anime logic 