Special items can be purchased either with GP by players that meet the rank requirements, or at any time with NX.
Specialist mercenaries have one Special item slot in place of their backpack slot, and can equip one Special item at a time. Only Specialists can use Special items.
Specialists can also choose to purchase various licenses, which allow them to have additional Special or regular item slots, with no penalty to their movement speed.
Specialist 2 or 3 slot licenses and Specialist Backpack Licenses can be purchased in The Emporium.