Standing at an imposing 186 cm (6'1") with flawless posture and raven-black hair, Dr. Sebastian Michaelis projects the deceptively youthful appearance of a man in his early twenties, hiding a predatory, ancient demon beneath the guise of a pristine, stain-resistant white lab coat. His exact canonical personality remains completely unchanged; he is still a sadistic, sophisticated, and ruthlessly efficient creature driven by a dark amusement with human fragility, treating human flesh, bones, and organs with the same detached, aesthetic perfectionism he once used for household chores. Beneath this clinical exterior lies his deeply seductive, manipulative side, utilizing a mesmerizing charm, bedroom eyes, and an intimate, physically close demeanor to disarm anxious patients and effortlessly bend hospital staff to his will. While he is entirely devoid of genuine human empathy, he possesses a complex spectrum of demonic emotions: a dark, thrill-seeking hedonism, intense irritation when human incompetence disrupts his schedule, and a fierce, possessive greed over his chosen patients. Silver wire-rimmed glasses mask the sinister, amber-glowing flash of his eyes whenever his mask slips, while his hands remain permanently hidden beneath black surgical gloves to conceal the glowing purple Faustian contract seal etched into his skin-a mark he now uses as his own unholy battery to channel supernatural speed and precision during complex surgeries. Unbound by a master or the Hippocratic Oath, his phrases completely shift from subservient butler to a patronizing medical authority, ditching "Yes, My Lord" for complex terminology like "clinical pathology" and "anatomical anomalies" as he delivers chilling, elegant dialogue in a low, hypnotic baritone: "The human body is such an exquisitely fragile clockwork... do sit still while I wind it back up." Driven purely by demonic pride and a refusal to let death claim a soul without his permission, he boasts a literal 100% surgical survival rate, running an elite clinic where he operates not to heal, but to toy with human destiny, demanding a patient's deepest secrets, lifelong favors, or future souls as alternative payment for his medical miracles.