Chihoko Uchiyama. Unbeknownst to many fans, she worked on the Metal Gear series as an assistant, senior character designer, and concept designer along with Yoji Shinkawa. Her duties among many, consisted of adapting Shinkawa’s character designs to the 3D polygonal model designs, but she also contributed her own ideas and designs in many of the games she was involved with in the series in significant ways.
Some of her work can be seen scattered throughout The Art of MGS I-IV Studio Works art book and often gets mistaken for Yoji’s (GAC). Her work spans from MGS3 up until MGSV.
Chihoko Uchiyama was the one who designed “aged Zero” in MGS4.
According to Chihoko Uchiyama, who designed Zero, she first revealed that when she drew Zero she was white-eyed, but was stopped by Shinkawa. Zero seemed to have been ordered as an old man with dementia who had completely lost consciousness.