|“||I've never been able to say no to a man with a dangerous alien biosphere.||”|
Dr. Raya Underhill is a Threshold specialist under contract at the Federal Bureau of Control. At the request of Dr. Casper Darling, she was brought in to study and resolve the extra-dimensional Mold problem that had been plaguing the Oldest House. Throughout their conversations and working relationship, Dr. Underhill is shown to be either completely oblivious or totally indifferent towards Jesse's authority as her direct superior, and insists that Jesse refer to her as Dr. Underhill rather than simply Raya.
Underhill was hired by the Bureau as soon as she graduated from university. She specialized in Threshold research and regulation, but after a decade, she had grown frustrated with the way the Bureau operated.
Underhill subsequently left the Bureau to become a professor, though ultimately the experience was not very different. Over the years, she stayed in touch with Darling, whom she occasionally encountered at conferences and other such events. When he contacted her regarding the Mold, she was immediately fascinated and returned to work at the Oldest House once more.
Official Bureau report indicates her time served at the Bureau was without incidents or demerits and was praised by those who formerly worked with her, including Dr. Darling. Her civilian behavior has been described as ideal, with the exception of an ongoing personal relationship with Dr. Darling that began during their time as co-workers in the Research Sector and revisited intermittently ever since.
Studying the Mold
On the 29th of October 2019, about four months after Underhill first began studying the Mold, the Hiss invaded the Oldest House. However, due to the Hedron Resonance Amplifier given to her by Darling and her workspace on the edge of the Mold Threshold being somewhat removed, Underhill was relatively safe from any direct attack. Nevertheless, the invasion prevented her team from keeping the Mold's spread throughout the rest of the Oldest House under control, and thus was unable to request additional staff to carry out further expeditions into the Threshold.
Upon meeting Jesse Faden, the new Director, Underhill tasked her with collecting samples of several Mold strains that, when combined, would make one immune to the fungus' toxic spores. In this way, she hoped to send someone deep into the Threshold to find the source of the Mold and figure out how to stop it from spreading even further. Once Jesse returned with the samples, Underhill was able to synthesize a pill that modified one's senses so that they would be disgusted by the spores of the mold, and therefore resistant to its parasitic nature. After administering the pill to Jesse, rendering her able to traverse the deepest reaches of the Pit, Underhill sent her off to locate the source.
Later, Underhill was aghast to learn that Jesse had killed Mold-1, but a sample from the creature did placate her to an extent. She informed Jesse that Mold-1's demise had brought a halt to the Mold's rapid spread. In the meantime however, several infected Hosts had managed to escape the Threshold and begun roaming the Research Sector. Underhill subsequently tasked Jesse with eradicating these as well, to ensure the Mold's proliferation was definitively stopped.
After the Hiss invasion
With the Hiss crisis and Mold-1 dealt with, Dr. Underhill chooses to remain at the Bureau to assist with the aftermath and continue studying the mold, though she notes that she's unable to leave until the Hiss are sufficiently contained in either case. Despite her hard exterior, she is clearly shaken when presented with the news that Dr. Darling is presumed dead, in spite of the critical way she referred to him otherwise. Similarly, Underhill is only barely able to contain her resentment towards Jesse for her decision to promote Dr. Emily Pope to Head of Research rather than her, making sarcastic mention of meritocracy in the Bureau.