At a meeting with En Masse during PAX, our own Bill Murphy and Carolyn Koh were told that TERA's endgame PVP will include a to-be revealed Server vs. Server element. 

The only details we have so far are that an opposing server will be able to invade the world of another server for riches and glory, but the defenders will be able to drive them back and then chase them into their own server if they're capable. 

En Masse wouldn't comment further, but they promised that more details will come around the time of the closed beta. 

Stay tuned for our PAX 2011 write-up on all things TERA later this week.  In the meantime, head over to our Game List page to read up on the game and its announcements.