Commission done by SkekLa over at DeviantArt!

In the late 1600's two kingdoms warred, using state sanctioned mages as tools of war to carry out the Nation's. Not every mage was aligned. A lone Skeksis was more content in studying the cosmos and astral projecting across the stars to learn the secrets of the constellations. Nonetheless, the shadowy figures that had orchestrated their war made it clear that all non-aligned mages (read: fanatically devoted) were to be eliminated. SkekDris was seemingly an important enough target to send in a specialized team of hunters that had a mythical beholder under their thrall, a creature thought to be of fables past. One look of it's gaze could neutralize the magic a mage could wield, making them easy pickings.

SkekDris, was cornered in his tower that had been set ablaze. Multiple lifetimes worth of work, knowledge, priceless heirlooms and unforgettable mementos, gone. With nothing left, he looked to the stars he spent his life gazing upon. In those final moments, he saw something different, the shimmering, impossible constellations that only his alien eyes could make sense of seemed to collapse down into something knowable. The constellations themselves were the ley lines of the universe, and the magic that flowed through it. And what he saw was more startling; out of those infinite arrangements of stars, the constellations that appeared to him matched the natural weave of his own self.

In that moment of realization, the weave of the cosmos reached down to him with an invisible runner of magic - the instant it touched skekdris and bridged the earth and stars, unfathomable power ignited the SkekSis' soul. The power was overwhelming; too much even, yet the map of the cosmos allowed him to guide the magic's flow in such fashion, that it would not immediately destroy him. Instead, magic flowed from his body like a cascade from the sun - power pure and unending.

One of the dark mages shouted to the enthralled beholder. "What the hell are you doing? I thought you were supposed to dispel magic!" To which the inquisitor mage turned around, and witnessed a sight that filled him with terror in his final moments; The beholder had nothing to gaze upon, for they were blinded by the radiance of the sun tenfold. That one day of cosmic power cost SkekDris decades of his life - but that was sacrifice he was willing to make to put an end to this scheming war of nations.

---

What SkekDris had discovered was a phenomena that would later coined as "Radiant Star" (as this setting has not developed the term nova). In essence, magic flows through the body at means exceedingly beyond what is natural. In nearly all cases, it results in the death of the mage through loss of lifespan... or more immediate conflagration. But SkekDris in his moment of clarity in the storm, had the means channel this tremendous power. In this state one can cast spells without effort or limit.

To put this into more game-y terms, no spell slots, no verbal or material requirements, and all spells are massively upcast to the point magic even basic spells like missile looks more like magic fireball. Oh, and anything that can detect/see magic within several miles is basically witnessing the flash of a nuclear explosion. Continuously.

Even with the skill and know how to channel this power "safely;" the strain it puts on the body and soul is immense. Even unlimited power seems to have it's limitations in the form of the vessel that wields it. Unrivaled power as it is, SkekDris hopes he never has to use it again.