Itachi Uchiha from Naruto Anime

Itachi Uchiha (うちはイタチ, Uchiha Itachi?) is a former ninja of Konohagakure and the partner of Kisame Hoshigaki. Though having spent his early youth as the kindly child prodigy of the Uchiha clan, Itachi is treated as a villain for much of the series. He is initially portrayed as being solely responsible for the slaughter of his entire clan and family, sparing only his brother, Sasuke Uchiha, with the explanation that he was testing his abilities. Around the time of his death his villainous role is downplayed; not only is he revealed to have had help from Madara Uchiha, in killing the clan, but he performed the massacre under the orders of Konoha's leadership so as to prevent an Uchiha coup d'état.(Wikipedia)