This does come with a slight downside, as the developers had been planning on giving everyone an extra character slot to include the Dark Knight, but there are currently some technical issues cropping up due for a hotfix tomorrow.
We're aware of the issue with the '13th character slot' coupon. We're working on the fix and will keep you updated.
— Black Desert Online (@BDO_News) February 22, 2017
Still, it’s a new class for those who like it, and it’s just a week away at this point. You can check out screenshots and an overview trailer just below, or you can just create a face you’ll like as soon as server maintenance is finished.