This set is made up of the five special rings that are given as rewards for winning the Colosseum. Being rings, only two can be worn at a time. Any combination of two rings will activate the bonus. The rings may be given to the Master Arbitrator, for 2 Colosseum Coins and 30% of your level, with a max of 140 million xp. Adding an Empyrean Crystal upgrades a ring to its enhanced version. This also changes the person it is attuned to to whoever adds the Crystal (givable). So you can ivory an unwanted ring, give it to someone else, and if they upgrade it they can then use it.