“The breath of life of the seven combined and set the stone ablaze in an iron flame.” 

This quote, which occurs in Chapter 63, is the inspiration for the book’s title. Violet spends the majority of Iron Flame trying to research how to fix the wards in Aretia so that the people who live there will be safe from venin and wyvern. She and her friends break into the Archives’ sublevel vault to steal the journals of Warrick and Lyra (two of the First Six who created the wards in the first place 600 years ago) to see if they recorded how they did it. Violet, Dain, and Jesinia work tirelessly to translate the texts and they originally think that the wardstone requires fire (“breath of life”) from a representative of each one of the six types of dragons (black, blue, green, red, orange, brown). However, Jesinia finally realizes that Lyra’s diary calls for seven breeds, not six. Violet and Jesinia originally think that this is impossible but Jesinia’s reveal causes Violet to have an epiphany. She finally realizes what Andarna has been hinting at for the entire book: she is not a black dragon and is, instead, a seventh breed that the Empyrean (the governing body of dragons) has kept hidden from humans. Violet’s discovery allows her to heal the wardstone at Basgiath after it is destroyed in the novel’s final battle and sets her on the path to track down the elusive seventh breed in the following book.