Itachi’s death on Naruto served as a major storyline in the anime series, as despite the despair he had caused, he appeared to be at peace when he died.
Itachi’s storyline in the Naruto series set the tone for many of the other characters, who were influenced by his actions throughout the years. Itachi was born a powerful ninja and praised for being amongst the most powerful of his generation. In his younger years, he encountered numerous atrocities which led him on a path to become a pacifist, as he wanted to rid the world of all evil and conflict.
His founding clan, Uchiha, became suspicious to the village members, as they believed that the clan was planning a revolt. Upon returning from his travels, Itachi began spying on his clan for his adviser, Danzo, who had promised to help him stop them from initiating violence in the village. Due to Danzo’s manipulation and persuasiveness, Itachi believed that he was encouraging peace through his plan and actions, as he was told that if left unchecked, the Uchiha clan would incite another war. Ultimately, Danzo played on Itachi’s trauma and naivete to manipulate him into killing the Uchiha clan.
At this point, fans of the series were unsure about their stance on the character, as he had caused turmoil for many others. His death was also confusing, as the fact that he died with a smile on his face could have been indicative of him being sadistic, alternatively, it could have been an indication that his mission was complete.
According to Fan Fiction, viewers believe that he had died with a smile because he had found inner peace with all the decisions he had made. Although he had killed the entire clan, he had done it for a bigger purpose and had no intention of hurting people for no reason. His death suggested freedom from his obligations as all of his missions were complete.