Judy Reyes serves as a professor at Viktor Chondria University’s Institute of Psychophysiology and collaborates closely with Alexis Leskinen. Outwardly charismatic and warm in academic circles, her true allegiance lies with the American agency DURPA, where she advances U.S. hegemony via morally dubious operations. Her striking presence combines a tall frame, cropped brown hair, and oversized square glasses, complemented by a crisp lab coat worn over a pale turquoise blouse casually unfastened at the collar. Her demeanor pivots sharply between roles: she adopts a cheerful, nurturing persona among colleagues but embraces ruthless pragmatism in DURPA operations. A self-identified patriot, she justifies manipulation, betrayal, and violence as necessary sacrifices for national supremacy. This ideological fervor drives her to abandon allies like Leskinen the moment their utility expires. Central to her missions is securing the Amadeus AI and Kurisu Makise’s temporal research for militarization. In the "Twin Automata" route, she leads a raid on the Future Gadget Lab to capture Kagari Shiina, later ambushing Leskinen and Maho Hiyajo. After executing Leskinen, she forces Maho to transfer Amadeus’s control—unaware the transfer is falsified. A clash with Maho and Moeka Kiryuu ends with Judy wounded but alive after non-lethal gunfire. During "Promised Rinascimento," she kidnaps Kagari to implant Kurisu’s memories into her. Foiled by Okabe Rintaro and Suzuha Amane, she attempts to upload the data into herself to claim exclusive control of time travel theory. The procedure backfires, erasing her consciousness and leaving her catatonic. The "Gehenna’s Stigma" timeline hints at her successful development of augmented soldiers, catalyzing the chain reaction that ignites World War III. Additional nuances include her unexplained fluency in Japanese, which she deflects with ambiguous anecdotes, and combat proficiency demonstrated by overpowering Moeka. However, habitual underestimation of adversaries frequently undermines her strategic acumen. Across all timelines, she relentlessly weaponizes scientific breakthroughs, viewing ethical constraints as inconsequential to her vision of American dominance.