Demon Invasion is a PVE event that lasts for 30 minutes and occurs 3 times daily. It is a very good source of Crystals to improve your skill levels and Demon Fruit which increases your base attributes.
The bosses progressively get harder, and as the event goes on you also temporarily get stronger.
Here is the able for what rewards you get per your total damage ranking in Demon Invasion
|1||Lvl.1 Magic Fruit Chest x10|
|2||Lvl.1 Magic Fruit Chest x8|
|3||Lvl.1 Magic Fruit Chest x6|
|4-10||Lvl.1 Magic Fruit Chest x5|
|11-50||Lvl.1 Magic Fruit Chest x3|
|51 and below||Lvl.1 Magic Fruit Chest x2|
-if you don't want to participate in this event and get basic rewards (gold, crystals, and 50+ prize - 2x Magic Fruit Chest), just simply do some damage and quit the event. You'll get your rewards after the event ends.