I hate linking to EW for anything but it has the exclusive info on who Forest Whitaker is playing in the movie.
I realize for some people this constitutes a spoiler but to me, if it’s officially-released info, it’s not really a spoiler. There’s character info on everybody else in the film that was issued today as well.
So if you haven’t clicked yet and stuck with this post thus far, the character is Saw Gerrera, last seen on The Clone Wars back in 2012. He and his sister were insurgents being trained on Onderon by Obi-Wan, Anakin, and Ahsoka. As you may recall, Saw’s sister kind of had a thing with Lux Bonteri, who had joined the insurgency, until she fell off a cliff and Ahsoka couldn’t save her. It’ll be interesting to see how Gerrera’s experience of being bitten in the butt by one insurgency would affect his being a part of another some years later.