During production of the first anime adaptation the author often visited the TMS Entertainment studio, where the voice actors asked for her advice about their characters. While nervous about giving advice, Hoshino was amazed by the work of most of the voice actors. Tyki Mikk's voice actor, Toshiyuki Morikawa, remembered the series' recording sessions as being "lively" because of the presence of many popular actors. After the anime wrapped, the actors (who became friends during production) kept in touch. For the sequel "D.Gray-man Hallow", the cast was replaced. Hoshino was surprised by the acting of Japanese actors Ayumu Murase (Allen) and Yutaka Aoyama (Millennium Earl) because they managed to bring out different sides of the characters not seen previously.