Back in 2015, she appeared as a contestant in the second season of the competition show "Unpretty Rapstar." She was able to make it to the final round, and eventually finishing in third place. Moon Sua is expected to be the rapper within the band. Apart from these two members, Mystic Story's upcoming K-pop girl group is also said to include Japanese trainees, excluding Takeuchi Miyu, a former AKB48 member and Produce 48 contestant, who left the company on May 3. Not much is known about the Japanese trainees of Mystic Story, but it is said that the trainees they introduced via Instagram will be the ones to make their debut.