Mana are a race of beings that alchemists can make pacts with, to unlock their true potential, and improve their skill with alchemy. Some Mana are less agreeable to pacts than others. _{[Like Flay's Mana of Gold, or all the trolling Roxis' Mana of Light did before it finally pacted with him.]}

... I have a pact with the Mana of Illusion. It's a little hard to explain, really.