Professor Gerald is a major antagonist of SIM - Termination, the creator of the Ship-Mice and a man who was known as a renegade even before his dealings with the main cast.
Professor Gerald was a gifted scientist but sadly his talent was tainted by a deep obsession with success, often at a rate of change which would be considered reckless to others - forever pushing both his own limits and those of his creations he earned a bad reputation amongst other scientists as a rogue whose experiments often caused trouble.
Despite this Professor Gerald was too valuable to be abandoned and since his eccentric nature was not enough for a criminal conviction he was allowed into the ISDF where he worked on the Ship-Mice project in order to provide humanity with a "companion race" which would pilot Gerald's visions of future space-travel, in which humans slept in hibernation during the long travels across the stars and the Ship-Mice tended to both their human masters and the workings of the stellar-fleet.
Many of his early Ship-Mice were failures, either dying or being born horribly deformed or slow-witted - unable to admit defeat Professor Gerald hid many of these "failed" Ship-Mice from public view as well as the eyes of his fellow scientists or ISDF Judges, eventually creating a Ship-Mouse that was stable both in mind and body.
Professor Gerald named this Ship-Mouse Jacob and began to call his experiment a "Jacob's Ladder" - the events of SIM City allowed Gerald to push the Ship-Mice project further and his reckless obsessiveness once again began to surface as he revealed Jacob to the public despite the hesitation of other ISDF scientists.
After Jacob failed to kill SIM in the V-Net Professor Gerald's cruelty surfaced and he inflicted both emotional and physical abuse on his creation before sending him to the "cage" alongside the other failed experiments - experiences that Jacob could feel as a result of being empathic, thus feeling the plight of the many failures calling out for help.
(more info shall be revealed after events in-story to prevent spoilers)