The company announced the closure of the fantasy title on the official site: "Unfortunately, we have come to a difficult decision to end this long journey we have enjoyed and cherished together. We understand that this will disappoint many of our players. We will be disabling client downloads and cash shop for the game on the 11th of December. The game will be closed on January 1st."
There is a silver lining to this, however. Webzen will be throwing a 400% XP and drop event from December 11th until Archlord's closure. In addition, the company urged the community to transfer interest to Archlord 2.
[Thanks to Skurvel for the tip!]