Void beasts were broken into tiers of their own that matched the general rankings. In fact, their existence is where the general rankings came from. A Tier 1 General could battle a Tier 1 void beast with 50-50 odds of victory. Of course, this calculation included the warriors under the general's charge as well. This was most definitely not meant to be a one on one battle. Stories of soloing void beasts were few, rare and exceptionally far between.
A Tier 1 General was allowed a million subordinates, ten Junior Generals, a hundred Captains and ten thousand Junior Captains.
A Junior Captain was at worst an Immortal Saint, however Junior Generals were at worst Immortal Celestials. True Generals varied in their ability though they were also Immortal Celestials at a minimum. But, not all of them were powerhouses with outstanding individual strength.