That's Catch 22 is a novella within the Digital Devil Saga series. As of now, the first of its two parts has been anonymously fan-translated.


Written by Tadashi Satomi, it was published in MediaWorks' Digital Devil Saga: Avatar Tuner ~The Master Guide I~ and Digital Devil Saga: Avatar Tuner ~The Master Guide II~ as two separate parts.

The novella is set in 2014 America and focuses on Heat O'Brien meeting Serph Sheffield during the murder investigation of his professor, Henry Harris.


  • Heat O'Brien - A second-year student, having skipped a grade, in Yale University's school of medicine. He is described as being eighteen years old with blond hair. Bearing a grudge against God after having lost his sister to DiGeorge syndrome at a young age, he is interested in medical science and genetics. Attends Yale's Berkeley College.
  • Serph Sheffield - A second-year student at the same university as Heat. He is the youngest in his academic year at sixteen and basks in the attention it garners him. He knows a lot about the students and faculty of the school. He aids Heat in searching for the answers behind Henry's death. Attends Yale's Davenport College.
  • Henry Harris (ヘンリー・ハリス) - A professor of genetics at Yale. He is forty-eight years old.
  • Allen Harvey (アレン・ハーヴェイ) - An FBI investigator.
  • Margot Cuvier - A woman from the World Health Organization who discovers the Cuvier Syndrome, complications caused by the crystallization of somatic cells. She lectures at Yale.