A spin-off novel series, "D.Gray-man: Reverse" by Kaya Kizaki, explores the history of a number of characters. The manga has been adapted into a 103-episode anime series by TMS Entertainment which aired from October 2006 to September 2008 in Japan and is licensed by Funimation in North America. A 13-episode sequel anime series, "D.Gray-Man Hallow", also produced by TMS Entertainment. It aired in Japan from July to September 2016 as a sequel to the first "D.Gray-man" anime series. Several items of merchandise have been produced, including two video games about the series.