Everyday, there is a simple trial where you get to play a short mission with a unique hero (different hero everyday) and try to meet its objectives. When successful, you will be rewarded with gems. For instance, on our 6th day in the game, the challenge provides Smoulder as the hero (take note that even though you haven’t acquired the pertaining hero in the given mission, you’ll still be able to play it) and should you be able to successfully finish the mission, you’ll be rewarded with 90 gems.
It goes as far as playing your 30th day – where the pertaining reward for that daily trial is around 500 gems. It does not cost you any energy points to take part on daily trials, although you are limited to 1 attempt. Should you fail on the attempt, you’ll be charged with gems instead for a re-try. The difficulty of the challenges in this segment also increases as you progress.