The Dark Ritual

The Dark Ritual is a technique book in Aretisia: Tenebris Dominus.

Description
When equipped, it lowers the Energy cost of abilities by 25% and doubles the max Energy and Energy Power of a single party member, but halves max HP and lowers defence by 40%. This makes it incredibly useful for Jeremiah and potentially Poppy, who both benefit from the doubled Energy power, but incredibly ineffective for Sophia, as most of her abilities use ATK and not EPW.