Vivian Garrahan was the CEO of Garrahan Mining, which was in competition with Daniel Hornwright and Atomic Mining Services. She hired Harold Frost to lead her research and development team to create the Excavator power armor. When the power armor was completed, she publicly challenged Hornwright to a mining competition between her power armor and their auto-miner machine. She believed that the desire of her employees to win would prove victorious, but despite their best effort they were not able to keep up with the machine. The loss badly affected Vivian which she took responsibility for the company's financial losses and even considering on handing over the company to her son Bryce.
Vivian, more than Hornwright, valued human miners over machines. She received a sample of hallucinogenic gas from HalluciGen, Inc. to use on strikers but she planned to send it back instead, preferring peaceful solutions. Even when her power armor failed to beat the Auto-Miner, she was still proud of the crew manning the armor for trying so hard.
Vivian Garrahan is mentioned only in Fallout 76.