Caelestia Potentiae are magic spells of the highest powers, spells capable of reducing cities to rubble and miles of land into ash. There is a Caelestia Potentiae for every living Ancient God. While it is extremely powerful, it is also extremely not worth it for any actual combat encounters. Casting a spell of this caliber requires utmost focus and concentration, time, and tons of flowing magic. Casting a Caelestis Potentiae typically requires about 30 trained magicians to come together for a few hours to focus on channeling the magic. Very few people have the power to cast a Caelestis Potentiae by themselves.
If one were to fail to cast a spell like this, it would cause everybody casting the spell to spontaneously combust and destroy the land around them in at least a mile's radius. Because of this, most deem it tactically not worth it to even consider casting a Caelestis Potentiae, and those that did have always met their ends in gruesome and untimely ways.