A Challenging Chest is a Restricted Instance reward sent to you in the mail after completing a Restricted Instance. It is given to you in a message in your mailbox, clicking on the icon on the bottom left of the message makes it appear in your bag (inventory) where you can open it to reveal a random reward. This can consist of one random Development Item or a Commander Card.
Challenging Chest Possible RewardsEdit
|Development Item||Commander Card||Box Drop Rate|