No, it's chinese server, all those words are in chinese not korean.
Somehow they started moving out from Keo (lightside map 1) at the very begining of the video, but the actual battle occured at pvp 1-60.
I think we won't be able to see such a scene on NA sever until at least 6 months later. It's certainly an exciting video to see. The other mmorpg in which you can see such a battle where 200+ vs 200+, is Shadowbane, and darn I sure miss that.