Board Thread:Questions and Answers/@comment-27026386-20160924005211/@comment-27026386-20160924060727

Chihiro Fujisaki, Miaya Gekkogahara and Yasuke Matsuda. None of them is seen interacting nor mentioning Chiaki. It is quite unlikely that the three of them created Chiaki. Despite, Chihiro appearing after Chiaki's death and Miaya Gekkogahara never really appeared in the despair anime.

Accordingly Yasuke Matsuda was part of the 77th class as the ultimate neurologist. Seemingly, it must be him. If not, it's likely Izuru Kamukura. Despite being the three collaborators barely even seen Chiaki before. Izuru Kamukura did say he wanted to test something, so he probably snuck into the lab and created the artificial intelligence 'Chiaki Nanami'.