Each member has to protect 15 War Coins.
During Preparation Day, players will select and evolve their best monsters (that comply with the requirements) to create their defense team.
Level up your Monsters and place Runes on them to make sure you are prepared!

You should also scout your enemies and set up a strategy with your team mates:
Determine who you will attack to maximize the number of War Coins collected by the team.

Good Luck!