Itachi Uchiha is Sasuke’s elder brother in the famed Naruto book and anime series.
Itachi is a member of the powerful Uchiha family, although his youth was marred by conflict. Instead, he decided to make peace his top priority, whatever the cost.
He almost killed the whole Uchiha ninja clan. Itachi used this extreme measure for dubious reasons: to prevent a revolt that would undoubtedly lead to war.