The Dark May Project (暗闇の五月計画 Kurayami no Gogatsu Keikaku?) was an experiment that used subjects who were most likely Child Errors, in an effort to replicate Accelerator's powers by using a similar pattern of ability operation. This was done by referencing the cognitive patterns of Accelerator himself in order to optimize the personal realities of certain espers taking part in the experiment. Kinuhata Saiai was once a part of this experiment which taught her to use her ability as an automatic self-defense capability that activates if she is attacked, similar to Accelerator's vector shield. Kuroyoru Umidori was also a subject in the project, and apparently killed all the researchers at one point, bankrupting the project.
Saiai stated that it wasn't usual for children of the experiment to end up well, as many of them ended up in dissection tables while scientists tried to figure out in which part of the brain the personal reality was located.
One of the after effects, of the project, is that Accelerator's personality may be ingrained into the subject. Umidori seems to be the only one that appears to have such side effects.