How To Change the Maximum Number of Players
From Civilization Modding Wiki
This is actually pretty simple (on a PC). Here are the steps:
- Open CvDefines.h
- Find "#define MAX_CIV_PLAYERS" and look over to the right. That number is the number of players allowed not including barbarians, 18 by default.
- Change the number to the maximum number of players you want.
- Save the file and do a clean build of the DLL.