Databook (データブック, Dētabukku), Several databooks have been released containing informations about various important or minor characters. The characters nationality, age, height, weight, and etc. have been revealed. Not only character data's are been added in the databooks, but also the relationship of the informing character has been revealed, also novels or original one-shots are also include within a databook. Not only those two, but also some omakes are also included to make the databook enjoyable and a interview with the author of the series.
By every databook, you will obtain stickers containing mostly the major characters of the series and a colour introduction, by the author.