The driving force behind 'Drug Candy' really comes from the two people locked in its messed-up, magnetic dynamic. Park Hajin, the male lead, is this incredibly successful and composed plastic surgeon. On the surface, he's the picture of perfection, but that just makes his hidden compulsions all the more jarring. His addiction isn't to a substance; it's to the chaotic, all-consuming affair he starts, which acts as his own kind of narcotic. Then there's Han Da-eun, the female lead. She's initially presented as a sweet, almost ordinary woman in a long-term relationship, which makes her descent into this secret world so startling. Her character arc is less about becoming a different person and more about uncovering desires and a capacity for risk she never knew she had. Their relationship is the entire engine of the story.
The supporting cast primarily exists to highlight and intensify the main couple's isolation in their secret. Da-eun's longtime boyfriend, Hyun-soo, represents the stable, predictable life she's supposedly built, making her choices even more confusing to outsiders. Hajin's wife is a shadowy but ever-present figure, the embodiment of the societal contract he's shattering. These characters aren't deeply fleshed-out individuals so much as they are pillars of the 'normal' world that Hajin and Da-eun are blowing up. The tension doesn't come from a love triangle in the traditional sense, but from the constant, nerve-wracking threat of exposure and the emotional fallout on these oblivious third parties.
What I find most compelling about these key characters is how they resist easy categorization. The manhwa spends a lot of time in both their perspectives, forcing you to understand their justifications without necessarily endorsing them. Hajin isn't a romantic hero; his obsession is possessive and often selfish. Da-eun isn't a passive victim; she makes active, devastating choices. The story works because it fully commits to portraying this specific, toxic symbiosis, letting the characters be flawed and often unlikeable, yet fascinating in their unraveling. Their chemistry is less about sweet romance and more about a shared, destructive hunger that feels terrifyingly authentic.