Beasts are overpopulating the realm, upsetting the balance of nature. As a natural enemy of Beasts, the Monsters are emerging to destroy them and protect their territory.
Let's start this off quickly: During this event, all Monsters get the Quick Starter passive, which gives them extra energy at the beginning of battle!
As for quests, there will be a new set of quests each day, as well as a few repeatable quests. If you miss something on one of the days, don't worry, the quests will all remain available until the end of the event! You'll probably want to complete all the quests though, because if you do, you'll earn a total of 100 Hopper tokens, enough to unlock the adorable killing machine.
Some quest payouts will vary by player level, but any quests that pay out tokens are the same regardless of level.
Edit: I forgot to mention that for the first day of the event, PVP Honor rewards are doubled, surprise! This bonus will end tomorrow at 3pm CST.
It seems that a quest went out with an incorrect number on Day 3. The "Buddy System Quest" counts for Day 3.