The Mages of the Yellow Flame were a group of occultists that were born from the Vallosian High Academy. Originally, The Mages of the Yellow Flame (before they were referred to by this name) were a group of scholars that were researching into the outer realms, beyond even the celestial realm of the gods and the infernal realms of the demons and devils. Their work was controversial, with most people, including the gods, believing that there was nothing beyond those realms. Solaris, a powerful mage, was the lead scholar on this study, with many believing he was wasting his time and talent. Solaris was obsessed with finding something beyond the known realms, and spent many decades in pursuit.
Eventually, Solaris claimed to have made contact with an entity from a realm beyond the known. He claimed that the entity was far more powerful than any god, devil, or demon, and when he made contact with it, his mind was filled with knowledge from beyond. The Vallosian High Academy were doubtful of his claims, as he had no evidence. Many even believed he had gone mad, as his entire personality seemed to have changed in an instant. Solaris became obsessed with the knowledge he was given.
Solaris began to preach that through the merging of souls, a perfect being could be created, and it would be more powerful than any higher being. Solaris used and taught a new kind of magic, the yellow flame, to his disciples. Those who were infatuated with the idea of power and ascending to godhood flocked to Solaris, joining his cause. With this new magic, the Mages of the Yellow Flame, as they began to be called, could melt people and fuse them together, combining their body and soul. Solaris said that once they found the perfect matches, souls with opposing qualities would cancel each other out and forge together as a new being, stronger and better. They were obsessed with creating the perfect being, merging the perfect candidates together to combine their strengths and weaknesses. The merging process was flawed, and resulted in many disastrous consequences, multiple souls trapped together in one body, constantly in pain and agony.
The Vallosian High Academy, already wary of Solaris, expelled him when they caught wind of his experiments. After being expelled from the academy, Solaris and the Yellow Mages had no more oversight, and began to experiment with humans. They abducted humans, performing merges on people without consent, trying to perfect their craft into a success. None of their experiments were successful, and they left behind their abominations, striking fear into the heart of the kingdom. Eventually, word began to spread that Solaris had mastered the yellow flame, and completed a successful merge on himself, becoming a new, more powerful being. He wasn't quite perfected yet, but he had merged with another soul, gaining tremendous power. He began his reign of terror in full force, nigh unstoppable. He could abduct people as he pleased, with no amount of mere mortals powerful enough to stop him. With every soul merged into Solaris, he became more powerful, closer to "perfection".
The gods began to be frightened of Solaris and the Yellow Mages, and for the first and only time in recorded history, the gods intervened in mortal affairs. They struck down Solaris and most of the Yellow Mages, banishing their forbidden knowledge, vowing to exterminate anyone that tries to practice the yellow flame. The exact details of Solaris's reign of terror and precisely what a failed merging looked like is a mystery, records have not survived the Godscar, but it was terrible enough that the gods saw it acceptable to interfere, something they vowed to never do.
The Story of Solaris and the Yellow Mages is a classic story told at Masterpool Academy, warning the students of the dangers of obsession and the pursuit of power, and meddling with forces beyond our understanding.