OF SPELLFIRE AND SPELLSCARS

Spellfire is refined, controlled, raw magic. In beneficient manifestations, it appears as a font of silver light and healing energy. In battle, it is a searing blue-white jet of all-consuming raidance. Some people are born with a natural ability to wield spellfire in all its natural power, whereas others can manipulate less potent expressions of it.
Persons gifted with the ability to wield spellfire can do amazing things with it, dependent on their skill, talent, and the amount of magical energy they have within them at the time. In general, spellfire can be used to heal, create blasts of destructive fire, or absorb magical effects it contacts, although the exact effects vary by circumstance and user. Talented wielders can release multiple blasts at once or even fly using the ability. The damage from spellfire is a mix of flame and raw magical power (half fire damage, half force damage) and therefore difficult to resist.
Right or wrong, legends hold that only one person in all Faerun is gifted with true spellfire at one time. Prior to the Spellplague, that person was identified as the lass Shandril Shessair, an orphaned kitchen-maid from a tavern in Highmoon of Deepingdale. As a result, Shandril was hounded by hundreds of mages, including many Zhentarim, Red Wizards of Thay, mages of the Cult of the Dragon, and others. They slaughtered each other and innocents who got in their way in pursuit of Shandril's power, and the girl's fate is unknown.
The legends lie, however. Multiple true spellfire wielders hide in the world, keeping their existence a secret to avoid the endless pursuit Shandril endured.
The lesser form of spellfire was once known as silver fire, and was once considered unique to the Chosen of Mystra. It could be used for a variety of more subtle effects, and its use could be taught. The Simbul, perhaps the most powerful Chosen of Mystra of the last century, taught its use to her apprentices. Other Chosen tutored powerful clergy of Mystra in mastering it.
Recently, larger institutions of wizardly training have made inroads in the use of silver fire, gaining greater understanding of the raw stuff of magic and channeling it in limited uses.
With the tearing of the Weave during the Spellplague, spellfire was unleashed in raw, uncontrolled fury, rolling over the world and transforming it. Thus, a new wrinkle was added to the scholarly understanding of spellfire: spellscars, marks left upon mortals by the magical disaster and its aftereffects. Many saw spellscars as the corroded echo of spellfire, twisted by the disaster that was the Spellplague. Yet the wielders of true spellfire secretly retained their gifts alongside these newly scarred.
Most creatures gained their spellscars not during the Spellplague, but afterwards, when they were exposed to areas still roiling with raw spellfire. Spellscarred individuals often developed unique abilities to use spellfire, but never without a price. Sometimes a spellscar was a physical abnormality, but more often it was an intangible mark that appeared only when its power was activated. An active spellscar might appear as jagged cracks of blue light racing across the forearms and hands, a corona of cerulean flame, a blazing blue glyph on the forehead, or perhaps even wings of cobalt flame. In all instances, blue fire is a sure indicator of a spellscar.
As with spellfire, creatures could learn to master their spellscars. In fact, some beings even traveled to lands still burning with the Spellplague in hopes of gaining a spellscar; such "scar pilgrimages" were encouraged by a mysterious organization called the Order of Blue Flame.