Every returning player is rewarded with a special daily login reward that grows on maintaining a continuous login streak. Be sure to bag the exciting Mystery Box as a reward, that can be earned on Day 7 and above.
If you fail to log in to the game for consecutive days, your daily login reward streak will be broken. The Daily Bonus Calendar will be set back to Day 1 and you will receive Day 1 reward instead of the missed day reward.
On the 7th day, you will be rewarded with a Mystery Box, which will have Mystery Rewards. And you will get the Mystery Box every day (after Day 7) until the daily log-in streak is broken.