Rebecca Yarros’s ‘Onyx Storm’ Is the Fastest-Selling Adult Novel in 20 Years The book, the third in a series, has sold 2.7 million copies in its first week, and provided yet another example of the romantasy genre’s staying power.

Rebecca Yarros’ ‘Onyx Storm’ Is the Fastest-Selling Adult Novel in 20 Years The book, the third in a series, has sold 2.7 million copies in its first week, and provided yet another example of the romantasy genre’s staying power.