From the publishers website:
A Free Web Enhancement for Transcendence
The dragons sometimes bring out underlying traits and abilities that lie dormant within all species. In addition to improving a specific characteristic, they also can draw forth a creature’s fundamentally animalistic nature or develop its natural connection to the ebb and flow of magical energy. These processes are much rarer than the other forms of tenebrian evolution. Only in special cases, when they work with a creature who has proven his loyalty and endured the dragons’ other treatments, do they confer them upon a subject.
Transcendence: The Arcana Evolved Player's Companion by Mike Mearls presents a wealth of new ways for your characters to evolve in interesting directions. And now Mike offers two all-new evolved classes to augment the book: the feral character and the mageborn.
This five-page free web enhancement expands the evolved classes available to players in Chapter One of Transcendence. However, you don’t need that book to use these classes in the Diamond Throne setting or any other Arcana Evolved or d20 System fantasy campaign.