Here is an official description of Warzone "The mode supports 24 players and features AI-controlled enemies. There are also "massive-scale" environments that are four times the size of any previous Halo map"
So yes, these are going to be some massive battles!
And to Delpen, according to all the articles I have dug up Warzone is two teams of 12 with some AI of course..... So you must be wrong or the articles I dug up are all wrong....