[quote=@Thinslayer]
Ooh, I just had a [i]wicked[/i] idea for the Witch's motivation: what if the Empire were secretly trying to build a Void army, and the Witch found out? That could definitely explain her animus against the Empire...
[/quote]

Isn't the witch supposed to be the big baddie of this story?  Seemingly invincible, building armies, GM controlled... probably best to keep her fairly simple.  If you play her like you're just another player playing your character, then we have a bit of a 'DMPC horror story' scenario.

I'd suggest just keeping her as the big baddie.  Maybe a twist down the line.   She's already a huge driving force in the plot and world.