February 29, 2017.
It is believed that an unknowable quantity of individuals were involved in the "Shichi Kyuu" experiment. However, during the third stage, this amount was lowered to a small handful of subjects. Of those subjects, three were able to recover and continue their lives; those that were not, however, have varied fates.
The full list of third stage subjects reads as follows: ██████, █████, ████, █████, █████, M██████, A███, K████, and an unnamed individual.
██████, █████ and ████ all returned to normal life, as mentioned above. No lasting effects of the experiment have ever been recorded in their behavior. Everyone else, however, have produced troubling results when attempted to research. Firstly, there is no evidence that M██████ and A███ ever existed in the first place. They appear to have been false identities invented by an unknown subject, possibly █████. Following the conclusion of the experiment, neither of these false identities have appeared since, suggesting that their use as personas was limited to the duration of the experiment, after which their host personality never required their services again.