VGFacts

The two main protagonists in the game, rivals Tokugawa Ieyasu and Ishida Mitsunari are voiced by real-life brothers Paul and Michael Dobson, respectively.  Their younger brother Brian Dobson also does the voicework for Goto Matabe'e, Ankokuji Ekei, Todo Takatora, and an Eastern Faction soldier.
Source(s):
http://www.behindthevoiceactors.com/paul-dobson/
http://www.behindthevoiceactors.com/Michael-Dobson/
http://www.behindthevoiceactors.com/Brian-Dobson/