What are Devil's Gems?
Ceres M Guide
If you play the modes in the game you'll eventually get some items called Devil's Gems. These items have their own category in your bag, so check which ones you have available. These gems can also be obtained in the Summon Shop.
These items enable you to learn a skill that triggers automatic effects. Different gems have different purposes so read their descriptions.
If you have a troop that you want an extra automatic skill, you can click "Contract" in order to equip it to your character. You'll be asked which Troop will sign the contract for that Devil Gem's power.
An interface will appear for the contract signing. You'll get the summary of the effects once again, and the cost if you'll want to terminate the contract. Take note that this uses rubies, so only use a Devil Gem if you are certain you want the effect for your character.
