From publisher blurb:
Unlock a New Kind of Mythic Power!
Sure, your character’s mythic path tells you about the kinds of abilities in which he specializes, and perhaps even gives some clue as to his ultimate mythic destiny, but it doesn’t say anything about where he came from, and what made him mythic in the first place. For that, you can turn to a mythic heritage. This new aspect of mythic characters allows for further customization of your mythic character. A mythic character can choose a mythic heritage in addition to his or her mythic path, and doing so grants him access to a number of unique abilities that are designed to reflect the flavor of his heritage, while also being of value to characters of every mythic path.
This installment explores the fire heritage, and characters that are in some way intrinsically connected to fire. They might be related through blood to a fiery creature, such as an elemental, or might be the child of a powerful spellcaster who is devoted to fire. They might have otherwise gained their mythic power from fire, having it bestowed upon them by a fire giant queen, or by purifying themselves in supernatural or magical fire. However they came about, those touched by mythic fire have dominion over flame and are able to imbue weapons with fire and enhance fire spells.