Itachi uchiha-before the massacre of the uchiha clan, sasuke felt that he was often over-looked. instead of being acknowledged, his father often paid greater attention toward his older brother, itachi. itachi was a child prodigy, graduating from the academy at age seven, mastering his sharingan at age eight, becoming a chunin at age ten, and becoming anbu captain at age thirteen. after itachis murder of the uchiha clan, he let sasuke live. when sasuke asked why he killed the clan, itachi gave reason that he wanted to test the size of his container. he left sasuke so that he could one day avenge the uchiha clan.