Hmm...does "KOTOR Sith" contain everything that Revan had + Sion + Nihilus ? If so:
Nihilus will drain the power from all the Jedi.
Mandalorian Army gets defeated by Revans troops.
That would leave
Clone Army, Droid Army
vs
Imperial Army, Rebel Army, Death Watch Army and all Revan had left after the Mandalorian wars. The clones and droids obvious get totaly outnumbered here and don't have any force users that could fight what is left of Revans Dark Jedi / Sith troops.