"Frankly, Dr. Jaime Reyes never planned on being a "hands-on" kind of doctor. He'd originally had his sights firmly set on the ivory tower, hoping to hook a nice, tenured professorship and settle down to blue-sky research. Then one week he started getting calls from "just an interested party, sir" — now he knows it was UNATCO — asking him about his published works on nanotechnology, bio-electrics, and one paper in particular about hypothetical ways to bypass the physical limitations of the human body.
Eventually he was recruited to UNATCO. He's an idealistic cynic, surprised to find himself gainfully employed, utilizing practical applications of his pie-in-the-sky ideas. He's delighted and dubious, always waiting for the other shoe to drop in this techno-dreamscape. He has all the notes on previous experiments (although no sign of the previous doctor) and as many tech-assistants as he could want. Jaime has adjusted his sights, and now hopes to produce a few modern-day miracles that will change the world. He's been supervising your augmentation since your first operations, and he's become your best friend in the world, next to Paul."
A doctor for UNATCO's Augmentation Division, Jaime Reyes attends to the medical needs of all UNATCO's soldiers, and provides JC with nano-augmentation canisters and upgrades from time to time. His office is also stocked with med-kits. Reyes is endeared to JC because of an understanding of his past, and eagerly assists JC upon his arrival at UNATCO. Reyes becomes dissatisfied with the organization as JC uncovers its secrets, but he is far less passionate about it than Paul. JC is given the choice to either keep Reyes in UNATCO as a covert informant, or to advise him to escape and assist the resistance. If Reyes escapes, he arrives at the Luminous Path Compound with an augmentation upgrade canister, which he gives to JC. If he stays at UNATCO, he eventually leaves and meets JC at the Enfant Terrible café in Paris. There he divulges to JC, Gunther Hermann's killphrase 'Laputan Machine'.