Many of the series' characters are taken from Hoshino's previous one-shots, both published and unpublished. She also modeled characters on her friends and well-known people. Designing and illustrating most characters was often difficult due to their beauty as well as their personalities. Critical reception to these characters has been positive, with writers praising most of the cast members as well as their development. The antagonists received a similar response. However, initial chapters of the manga, or episodes of the anime, attracted some criticism as a result of some of the characters feeling generic. Critics praised the voice actors for both the Japanese series and the English dub.