All Commanders above level 5 can enter Black Market and exchange Keys for chests. You receive Keys for each battle. Bonus amount depends on the place you take in the team. You can also purchase Keys. Using Keys, you can open three types of chests:
- Bronze — 10 keys;
- Silver — 100 keys;
- Golden — 1000 keys.
There’s also a Super Chest that you get for free after opening a certain amount of regular ones. The progress bar above shows how close you are to it. The more valuable chests you open, the faster the bar fills.
NOTE: Every 4 weeks Black Market closes its doors for a short time to refresh the stock — mind the timer. If you have any spare Keys by that moment, they will be automatically converted into a loot prioritizing most valuable chests. If you have fewer than 10 keys, these will turn into 1 Bronze chest. For example you have 1823 keys left. By the time Black Market closes it will bring you items from:
— 1 Golden chest (1000 keys);
— 8 Silver chests (8 x 100 keys);
— 3 Bronze chests (2 x 10 + 3 keys on top).
You can get more info about Black Market here.