Guardians

What is a guardian ?
A guardian is a monster that you found in the egg at Guardian Island which whom you contract, then he'll help you along you adventure.

You can choose which one you want in the guardian tab and assign different one to boost differents stats.

Finally you can give them some Summer Juice to improve their stats, once they're at lvl max, you can make them evolve to a greater rank, which will give star to the guardian.