(Note: This voice of Itachi is from the dub)

Itachi Uchiha is the bigger brother of Sasuke Uchiha. Itachi killed his entire clan, but left his brother alive. Itachi at a young age was a very powerful ninja, even joining the Anbu Black Ops. Itachi joined the Akatsuki, where he trained under Pain, and became even more powerful when mastering his Sharingan. 

Itachi's voice is quite deep, bland, and yet sometimes quiet. His voice should be as close as the dub voice actor, Crispin Freeman.