Completing specific conditions unlocks Achievements, which reward you with items, currencies, or even titles.
You can check out the Achievement menu from the menu in the top right side of the screen to view the different types of Achievements and what is required to complete them.
Some Achievements involve multiple steps, and each step is displayed as a trophy on top of the [Get Reward] display.
Achievement information will be different depending on the character level or game progress, so get ready to obtain different types of Achievements!