As an Uchiha, Sasuke possessed something called the Curse of Hatred. The Curse of Hatred causes Uchiha to love something passionately, for Sasuke that is Itachi and the rest of his clan, and become consumed with hatred after it has been taken away. After the Uchiha Massacre, Sasuke's hatred was focused on Itachi, for killing his clan, and this drove Sasuke to become a Missing-nin. Only after Obito tells Sasuke about Itachi's secret mission, Sasuke focused all his hatred for Itachi onto the Village Elders, resuming his love for Itachi in the process. Sasuke's Curse of Hatred continued to consume him until he didn't care who died to achieve his revenge and he was willing to sacrifice his allies to do so. At his lowest, Sasuke said he wished to destroy the entire village and everyone in it, because of how they indirectly benefited by Itachi's mission and death. Only after Itachi was reanimated and spoke with Sasuke, did Sasuke begin to question his path. Sasuke had Orochimaru revived so Orochimaru could reanimate the first four Hokage, so Sasuke could question Hashirama on what "being a shinobi" meant. Hashirama told Sasuke its was to reach peace even at the cost of personal sacrifice or death. Sasuke, realizing that Itachi's Will of Fire was similar to Hashirama's, decided to protect the village and fight against the Akatsuki to protect his brother's sacrifice, apparently releasing Sasuke from his Curse of Hatred.