Julius Preterius (formerly)
Dr. Gray was a colleague of Julius Preterius in his cat experiments.
Gray was a dark-skinned man with dark eyes. His facial features are hidden behind a surgical mask. He had black hair and appeared to be African-American.
He worked alongisde Ziebold as well and presumably left alongside him when the project began to lose funding and looked more and more like a failure. His ultimate fate is unknown.