Drag-On Dragoon 3 Story Side is a novelization of Drakengard 3. It is written by Jun Eishima and supervised by Taro Yoko, the director and scenario writer for Drakengard 3. Eishima has previously written novelizations for both previous Drakengard games, as well as character stories and supplementary mangas for the third game.
Eishima, commenting on her blog, said that while Endings B and D of Drakengard 3 seemed to lead into the original game, there was in fact no direct narrative connection. The book was intended to provide the narrative link between the games.
The book was released on 28 August, 2014, eight months after the game's Japanese release and three months after its international release.
The novel is told in the form of a narrative by the male One. It retells the events of Drakengard 3, detailing a fifth branch of events, aka Branch E. Events bear similarities to both all endings of Drakengard 3. The book chronicles the quest of the Intoner Zero to kill her sisters and herself, as they are manifestations of a flower that will destroy humanity. The book also details the origins of the Cult of the Watchers, Pacts and the Seal system.