Ceres, Celestial Legend is the third manga series written by Yuu Watase. She based it on the legend of the tennyo and her stolen hagoromo. This legend is the basis for one of the most performed Japanase Noh plays, Hagoromo. It is the Japanese version swan maiden, with versions from other cultures also being mentioned as the series progresses.
As with most of her serials, Watase planned the basic story line of Ceres through to the end before beginning work. She notes that it is easier to work this way, but that even with planning sometimes the characters will "move on their own" and refuse to follow her original plans. When she reaches the end of the work, though, she found she could understand why they did so. Watase noted that one of the hardest parts of writing a serial manga was having to plan for the cliffhanger at the end of each chapter. She wanted each to be something that made the reader want to know what happened next, so they would want to keep reading.
To enable her to accurately depict the many locations used within the series, Watase traveled to Miyagi, Okinawa, and Tochigi to visit the locations where legends say tennyo landed. She was able to negotiate entry into some normally closed to the public. The characters in Ceres are not based on real people, however Watase notes that each one reflects some part of herself, as does the story as a whole. For example, Watase incorporated her thoughts on genetic engineering and other new technologies through the character of Kagami. While she feels such technologies can be useful to society, she feels that they should not be abused. Kagami is Watase's reflection of her view of how people should not be, in his cruel disregard for the lives of the celestial beings he creates. Watase purposefully left Ceres' true nature ambiguous in the manga ending, never clearly stating if Ceres is an alien or truly a being descended from heaven. She notes, however, that part of the reason for this was that it wasn't something she'd thought about. In reflection, she felt Ceres was a symbol. In Japan, men are considered the dominant sex, and Watase notes that as a woman there are things about the system that anger her, such as men saying she is "just a woman." Ceres became a story about the relationship between men and women. She also wanted to show that while the tennyo and the humans in the story may have come from different origins, and evolved differently, they also were still the same living creature in the end, with similar feelings and thoughts.