Nothing comes to mind, just thinking of using existing slots for more functionality. However there are many types of JJANG's, in Quest you can win some that grant a small amount of elemental resistance, or +1 Max Weight. Other times you can use it as a Cosmetic aka VIP JJANG or when we Staff equip our JJANG which states our role.
JJANG aren't those small animal critters lol, that's from the Cosmetic Box.