It was originally scheduled for september 2 2016 but it was postponed for unknown reasons. Later Scheduled for April 4 2017, but changed to March 3 2017. March 1st announced another delay, with the new release date set for August 4th, 2017.
The confirmation of the release was given on july 14 along with the release of chapter 225. The cover illustrated by Katsura Hoshino was revealed as well.
Summer 2016 issue of Jump SQ Crown provided some samples of the fanbook:
Some other samples were given with Winter 2017 issue of Jump SQ Crown.
|Manga Omakes:||Character Profiles • Discussion Room • Komui's Discussion Room • Komui's Discussion Room Special Edition: Noah's Ark • D.Gray-man Investigation Series (?) • Weekly Jump Polls • Character Bedroom Sketches • The People of D.Gray House • Pointless D.Gray Stories|
|Anime Omakes:||D.Gray-Omake Mini Theatre|
|Fanbook Omakes:||Zone (Robin/Julia) • D.Gray-man Official Fan Book Gray Ark • D.Gray-man Illustrations Noche • CharaGray • D.Gray-man Official Fan Book Gray's Memory • D.Gray-man - Artbook - Gray Walker|