Darkness of Enigma (DOE) was a secret project of General Resource, starting on 2028 and lasting until 2033. The goal of the project was to study next-generation aviation and future neural control systems. The X-49 Night Raven was the ultimate product of said research. It was directed by Martha Yoko Inoue, who joined GR three years before it was initiated.
In 2031, child prodigy Rena Hirose joined General Resource and was used as a test subject on DOE. After an interview with Hirose, the project was revealed to the public, and her involvement caused the company to suffer criticism over ethics. The chief General members responded by ordering the killing of all personnel involved, including Yoko, and the Night Raven was kept hidden.
- The project, alongside General Resource, was directly mentioned in Ace Combat Infinity as part of the development history of the aforementioned Night Raven.