After beginning "D.Gray-man", Hoshino considered continuing to use the name "Zone" and also contemplated naming the series "Dolls" or "Black Noah". She chose "D.Gray-man" for its several meanings, most referring to the state of Allen and the other main characters. Although the title's meaning was not completely explained, Hoshino said that the "D" stands for "dear". According to the author, she got most of her ideas for the series while sleeping in her bathtub for six hours. One exception was the second-volume plot, based on a Noh story entitled "Koi no Omoni".