Key

Keys are the items required for playing Special Episodes, i.e. Ghost Pirate's Island of Coins and Tower of Frozen Waves. A feature introduced in the New World season, it refills one every 20 minutes until there are at least three keys. They are otherwise obtainable through purchase with Crystals and Hearts. Purchasing with hearts can only be done at maximum 5 times a day, costing 20 to purchase one key. There have now been other ways to obtain keys, such as buying them using medals, with the maximum amount of keys you can buy from the Medal Exchange Center being 20.