Dr. Trintignant was a surgeon who operated on Yellowstone in the period preceding the Melding Plague. He specialized in extreme cybernetic alterations to the human body, and was himself heavily transformed.
He filled a niche in the decadent Chasm City society, where body modifications was common among the upper classes, although he went further than most. Operating in a gray market, tolerated by society but thought of as perverse, he was able to find enough willing subjects to gain considerable knowledge in turning humans into improved cyborgs.
Trintignant started his career as an experimental cyberneticist, and gained a reputation for fearless innovation. Calvin Sylveste gained an interest in him, and recruited him to his own research team. However, after several of his subjects later claimed that they had not been complicit, the Doctor was charged with kidnapping and mutilating them, and went underground. No longer able to further his study by experimenting on others, he turned to his own body.
After years as a recluse, Roland Childe recruited Trintignant to his expedition to Golgotha. Here, the Doctor had the task of operating crew members who were damaged inside the Blood Spire. Initially merely replacing limbs with prosthetic, he was later given free reign to modify the bodies of Childe and Richard Swift as they grew more obsessed with reaching the top of the narrowing Spire.
Considering Swift his finest work, and unwilling to ever be persuaded to reverse his severe, albeit reversible modifications, Trintignant programmed his operating table to disassemble himself, apparently comitting suicide in the process. Although unable to return to his human form, Swift returned to Yellowstone and brought the remains of Trintignant with him.
Somehow, sympathizers of Trintignant came in possession of his body, and although he had claimed to effectively have commited suicide, this was not the case. Alive but in pieces, he at some point appeared to be imprisoned in the Rust Belt bestiary of Ursula Goodglass, on display to feed the morbid fascination of the Circle.
However, Goodglass had recruited Trintignant to take revenge over her nemesis Grafenwalder. Because of the Melding Plague, which had erupted during the Golgotha mission, the assembled Trintignant lived mostly inside a palanquin, posing as Goodglass's husband. Grafenwalder ended up as what was likely Trintignant's first human specimen in years.