We call it the breath of Olori, the essence of Olori.
Olori breathes out its sick, vile breath at us. Olori curses us with its vile tongue. Olori hates the ants on its infinite skin, us petty insects in this dying world. Olori is a world of deathwishes and deathtraps, a continual fount of destruction and anguish. Olori is a world of scarce food, little water, and dusty, stale air, scented with an ever-present hint of smoke or unfiltered filth.
This planet of hatred coughs up its own life to fuel the death it seeks. This world-essence is called the breath of Olori. It's birthed unto the surface and the arteries of Olori in various forms - bleeding crystals, desecrated altars, spun unholy threads, coagulated pools of light-sucking blood - but no matter the appearance it takes, any invoker of any Guild can recognise it, as well as draw the breath of Olori out and purify it for use, rolling its pristine white vapors and capturing it in their mantles.
The invokers bend and twist the essence of Olori into various forms. Like white light, the pure form of the breath of Olori is itself composed of many lesser, specialised forms. Some of these forms are useful in powering the beacons of the Guilds, burnt away to stave off the turmoils of Olori; others are useful in the creation of food, drink, or other material goods; the occasional piece is useful for the healing of wounds, the acceleration of time, or the augmentation of memory. A very few are useful in the imbuing of arms and armour with magical power.
The breath of Olori was meant to make our cities fall. Instead, it has become all we need to survive.