I was thinking about changeable shields. Like actual shields, versus a shield code. No one really makes actual "shield" shield codes that much anymore anyway. You can keep the shield codes then just call them something else. Shields however, would be entirely something new. They will all be equivilant, but serve different purpose. You start out with a spar shield. Your basic noob shield that can block one sword hit (then has to recharge) and can block a certain amount of arrows if being consistently fired upon. The sword icon can have a tiny health bar that slowly dwindles if you get bombarded with arrows or completely goes down if you use it for a block a melee. A mirror shield has a little more arrow resistance than the spar shield, but it also reflects any arrows back at the shooter too. However, if you are meleed the shield bar will completely vanish and have to recharge. The bomb shield is only able to use one block before recharge, which is either the sword or a bomb blast/fire breath. Any projectiles will imediately pierce the shield. Tower shield, 5 sword blocks. Gives slow movements and can be defected by an arrow or bomb. You are limited to one shield at a time in your inventory. If you wish to change it you must visit wherever you obtained it and you can simply swap out. That way someone can't just use another shield whenever their old one needs to recharge.

Edit: Forgot to mention, you may not spar with any other shield. The secretary at the front desk of the battle arena would be able to swap your shield for a spar shield in order to participate. Afterwards, you are free to pick it up or continue using it.