The actors name is David Warner. He also did a number of great Star Trek episodes and at least one movie; Star Trek VI where he played Chancellor Gorkon. You can get the whole cast from Baldur's Gate 2 from
www.imdb.com
I wouldn't say that BG2 was inspired by any of the aforementioned films or tv shows...the concept of someone who falls from grace, is exiled and then returns for retribution is an old theme that echoes through many cultures and mythos.