Letter Quest: Grimm's Journey Remastered

Quests are available only in Story mode, and 3 are available at any given time. They can be viewed during battle or at the Story mode map. Completing quests rewards you with a pretty good amount of crystals, and completing this usually requires doing something pretty simple (use the letter E ten times, use 20 corner letters, etc.) so make sure you stay aware of what quests are active and work toward them as often as you can while playing. When you finish a quest, a new quest takes its place.

There are 70 quests total in the game, and you also have the option to skip quests (which also counts as completing them) by paying gems. This may seem backwards as first, since you'll want as many gems as possible to buy upgrades, but you'll likely collect all stars before finishing all quests, and since it costs 100 gems to skip a quest, when you're done with Story mode you should have more than enough money to skip all the quests you have left, unlocking this achievement once they're all cleared.