Every time a new class is released, all players will receive a free temporary character slot. It will not be permanent. NCSOFT wants all players to To get your free character slot. I believe that the extra character slot is part of the June 22nd update. They stated previously that it will be the case with every new class release. To get your free character slot. In other games when it's similar like this, they increase the max amount of slots when a new character is released, sometimes even if you only 9 character slots? - General Discussion.
Blade and soul new character slots Video