Dark Horse has created an adult coloring book program to launch on October 5. The series will debut with the coloring books, Avatar: The Last Airbender and Serenity. Each adult coloring book features 45 pages of original artwork created specifically to be colored in on thick, heavyweight 10- by 10-inch pages. The coloring book is filled with original black-and-white illustrations by artist Jed Henry and produced in collaboration with creators Michael Dante DiMartino and Bryan Konietzko.