Dilan spends some time explaining everything that happened in the Prison Gate. He also told them that he knew about the small possibility of his Divine Essence Crystal mutating. The mutation of an Essence crystal was usually random and there were rarely entities with a mutated high-ranked Essence Crystal.
The information on Mutated Essence Crystals was not much, and it was even less for Divine Essence Crystals. As for the type of mutation, there were often elemental affinity mutation or new abilities that were created when an Essence Crystal mutated.
Unfortunately, the creation of a flame such as the Flame of the Beginning was not even something Dilan knew much about…and he read lots of books in the Library of the Great Wise.
He had been lucky to survive if one could consider it luck for someone Undying to survive a certain predicament. Dilan died more often enough to understand that he was not supposed to be alive anymore.