Any Pantheon heads had a look at this match type on multiplayer? Really fun if you enjoy a true co-operative style of play.
Captain basically means you control a Unit within the army (of 6 players) not the army itself. The co-operative nature of this game type is far greater than any other mode type. Chances are you tried skirmish, its just a normal deathmatch mess of no co-operation and just random killing, but captain is very strategic, if you are versing a team that is playing together well, you will HAVE to pull it together to beat them, include real strats into your defence or attack and all together i think this mode is the most fun i have had co-operatively online in a long time.
Anyways,if you have the game i'd highly reccomend checking out this game mode.