Challenges

Note: Scrolls do not help you in Challenges.

Quests
Complete missions with your squad in order to gain rewards. Some tasks allow you to choose your team, others are limited based on element, such as the Ore missions requiring Sun characters. Rewards are weapon upgrade components, gold, character upgrade potions, and Jade.

Element-limited missions do allow you to use characters while they are "away" on Expeditions.

There is no entry cost. You can only do 5 quests per day, plus more as you buy VIP levels. Completing two quests is one of your daily missions.

Fortress of the Deceased
You can try difficult, high-risk missions by spending 1 Jade piece. The missions give less gold than Adventures of similar difficulty, but they do not cost you bread and they are more likely to give you good items. You can also get a clover or, at high levels, multiple clovers!

Gap of Dimension
Three times per day, you can complete missions that will drop 3 random items as a reward. You must choose from a random list of characters and include the chosen character in your team. You can choose the difficulty level, but you must complete missions with the same character to access difficult missions. Difficult missions are more likely to give good items.

For every 10th Gap mission you clear, you receive a 3-5-Star equipment lottery.

Kingdom Defense
Twice per day you can challenge a series of bosses. The bosses rapidly increase in difficulty, and your characters lose health quickly even if they are not being hit. Slain bosses drop stones which can be crafted into item upgrade stones. (Note: You can only carry 9999 of each stone piece. They are expensive to craft, but it might be worth crafting some if your inventory is full.  They are nice to have if you run out of upgrade stones.)

You receive a score for each boss you defeat. Defeating them quickly gives the best score (so it helps to have some high-damage characters early in your battle order). You receive weekly rewards in the form of gems for having a good score compared to other players, and you receive daily rewards in the form of Rarity Upgrade Stones for having a good daily score. Check the reward guide for the daily reward values. All your characters participate, even if they are away on Expeditions. You can change the battle order. There is no entry fee.

Arena
Your active squad fights 3 of the strongest characters from a random selection of other players. (Sometimes you fight yourself!) You can win up to 10 battles daily. The reward is Red Cubes, which you can spend on (good!) equipment at the merchant in your house. You can control your group in the Arena, unlike in duels.Each day, the character elements receive random bonuses or penalties, listed at the top of the Arena screen. These apply to you, not the enemy, so they can be very helpful (or inconvenient). There is no entry fee and you may retry each battle as often as you'd like.