There was a post about this awhile ago. No one knows for sure how that will work (it may be awhile until we know since the online campaign will be delivered after the Xpack is released).

My opinion was that all turns in the online campaign should be simultaneous. What that means is all players make their moves without any knowledge of what your opponents are doing that turn. When all players have hit "End Turn" then you see all the moves that happens that turn. You will get some interesting things like you invade province A from province B while your opponent in province A invade province B.

The key is no one has the advantage of making the last move knowing what everyone elses moves were.

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