Allies are helpful NPC's that can gather riches and rewards for you! Each Ally will have treasure for you to collect once every 24 hours.
To claim your rewards, you must first locate the Ally. Once you find him, give him a tap and claim your reward!
When you collect your reward, you will see a screen similar to this showcasing what you received:
Note that after claiming your reward the timer is now reset. (There is also the option to bypass the timer using Platinum)
Be sure to check back every 24 hours so that you don't miss out on your rewards!