The First Templar has only been released in Europe, but the DLC that has been packaged with the Special Edition is now available for purchase from the marketplace in North America and Europe. The DLC adds six achievements worth a total of 250G.
Caught by the vile Byzantine, you have to survive the perils of the Arena. Fight for your life, face the Gauntlet and stage your escape. Chose who will stand beside you as you confront the Byzantine and his minions."The First Templar: The Arena" DLC costs 400 MSP and is available to buy from here.
The First Templar is due to be released on May 10th in North America.
We've got the full list of The First Templar achievements - check the list for guides to unlocking them.