Besides the Lord and Muse, there must be twelve taking up the 12 classes and 12 aspects, no overlaps (Lord and Muse will overlap the classes once). Zeratul seems obvious, but for everybody else, idk. This means there will be 12 characters, one large antagonist (Lord), and one large protagonist (Muse, which doesn't necessarily have to be a good guy, just a protagonist).
Main characters first please. (and PLEASE only canon characters)
What I have so far (not necessarily set in stone):
The Fallen One: Lord of Void
Sarah Kerrigan: Muse of Mind
Zeratul: Seer of Doom