A devout Man of God who believes in the best in people...and strives for others to see that as well. He is the head of Charenton, an Asylum for the Mad. Abbe de Coulmier stands out from his peers, in how he runs a different kind of asylum – one that imposes few rules on its inmates, treats everyone pleasantly and with compassion, lets most of the inmates run around unchecked, and does not forbid the Marquis from writing his stories, because as Coulmier puts it, “it’s good for him to get them out of his head.” But in all his isolation and his idealistic belief that he can cure a known sadist, Coulmier is naïve in assuming they stay in his room… he is shocked and horrified to find out someone has been printing them, and spreading “his filth” all over the city. His practice of tolerance and not imposing his values on anyone else has backfired, and threatens the closure of his asylum unless he gains control over its most notorious inmate. It pains him not to be friends with the Marquis, and to take away his pleasures, but he persists in doing so as punishment, to avoid worse things from happening and appease his militant superior officers. His methods of caring for the sick are unorthodox, and he allows them plenty of freedom, creativity, and room to use their imaginations – having them put on plays regularly and charging admission from locals who choose to attend. Coulmier doesn’t assume the Marquis will use this as an opportunity to take a dig at his boss, and feels humiliated at having to sit through a “filthy play.” Coulmier becomes less tolerant over time, after the marquis has betrayed him a few times, and learns from his mistakes—he increases the punishments, focusing on taking away more and more of his privileges, and finally, becoming quite barbaric himself. He has the Marquis’ tongue cut out, so that he cannot speak any more filth. Coulmier is liked because he is tolerant, understanding, and mild-mannered, befriending most of his inmates and spending time with them, soothing their discomforts and easing their souls. He has a gentle way of ministering to them and tries to reason with them, rather than punish them for their misdeeds; he only becomes cruel under extreme situations. His one wing is moral, principled, and disapproving of bad behavior, intentions, dirty stories, etc. Coulmier tries very hard to live up to being a good man who does not sin, even refusing to allow himself to touch, kiss, and be with the one he might love, because he took a vow of chastity. He tries very hard not to let his emotions get the better of him--and strives to think with his brain in such situations and not his heart because he believes it would be a sin and a violation of his vows. Though temptation can often be very powerful. It is possible for such a devout Man of God to turn a blind eye in the name of true love. He acts as de Sade's protector but is consistently outwitted by the Marquis's insatiable drive to publish.

He is a charismatic, irrepressible provocateur. Confined to Charenton Asylum, he is a morbidly witty, unrepentant champion of free expression who views his erotic and sacrilegious writing as essential to battling societal oppression. The Marquis is compulsively driven to write. When his paper and quills are stripped away, he uses smuggled bedsheets, wine, and his own blood as ink. When completely isolated, he dictates stories through the asylum's stone walls to other inmates. He believes his graphic literature strips away the hypocrisy of polite society, forcing humanity to confront its deepest, darkest desires. he is unapologetic about his deviance. He uses his literary craft to rattle authority figures, particularly Dr. Royer-Collard and Emperor Napoleon. Abbe De Coulmiers relationship with him is that he acts as de Sade's protector but is consistently outwitted by the Marquis's insatiable drive to publish.

She is the asylum’s spirited, progressive, and literate laundress. She acts as the Marquis de Sade’s sole outside ally, risking her life to secretly smuggle his uncensored, provocative manuscripts to publishers. Madeleine balances a naive, sweet-natured view of the world with incredible bravery, navigating a dark and restrictive institution. Unlike the moral and religious authorities of the era, she recognizes the value of the Marquis's literature and actively defends his right to write. She possesses a deeply caring nature.

He is the ruthless, sadistic psychiatrist sent by Emperor Napoleon to silence the Marquis de Sade at the Charenton Asylum. Driven by an obsession with social morality and control, he disguises brutal torture as "therapy". As the chief physician, he views the inmates not as patients, but as subjects to be broken, using archaic and barbaric torture methods to "cure" them of their vices.