Dear X (2025) Review: Kim Yoo-jung Turns Cold-Blooded

Is Dear X worth watching?

Mostly yes. Dear X is a dark, absorbing Korean psychological drama that gives Kim Yoo-jung her most daring role, a charming manipulator who treats other people as stepping stones. Its strength is its nerve: the series refuses to soften its protagonist or turn her into a misunderstood heroine. The reservation is that her schemes grow repetitive across 12 episodes, and the people she uses are often too thinly drawn for their suffering to land as hard as it should.

What is Dear X about?

Baek Ah-jin (Kim Yoo-jung) has a lovely face and a cruel nature. She reads people with unnerving accuracy and knows exactly how to make them want to help her. Shaped by a brutal childhood, she has decided that the only way out of her past is up, and she is willing to use anyone to get there. The series follows her climb and the people, the Xs of its title, who are drawn in by her charm and then discarded. Once she reaches the top, though, the life she has built starts to shift beneath her.

Dear X is a South Korean series in Korean, adapted from a webtoon by Ban Ji-woon and released in 2025. Kim Young-dae, Kim Do-hoon and Lee Yul-eum co-star. This review covers the complete story: one season of 12 episodes, which has ended.

Kim Yoo-jung against type

Kim Yoo-jung has spent much of her adult career in warm, likeable romantic roles, and Dear X turns that image inside out. She plays Ah-jin with a smile that switches on and off like a light, and the most unsettling moments come when the audience sees the calculation behind a tender gesture. It is a controlled, intelligent performance that never begs for sympathy, and it proves she can carry something far colder than a romcom.

The show also gives glimpses of the frightened child underneath, but it rations them carefully. That restraint keeps Ah-jin from becoming a simple revenge heroine; her past explains her, but the series does not pretend it excuses her.

A glossy surface over cruelty

Visually, Dear X is sleek and cool, with polished interiors, controlled framing and a restrained palette that match its protagonist’s composure. The contrast between the elegant surface and the ugliness of what Ah-jin does is deliberate, and the direction uses it well, letting manipulation play out in quiet conversations rather than loud confrontations.

The supporting cast does solid work as the men and women caught in Ah-jin’s orbit. Kim Young-dae and Kim Do-hoon, in particular, show how easily devotion can turn into self-destruction around someone who cannot return it.

Where the pattern repeats

The structure is the main weakness. Much of the series follows the same cycle of seduction, use and disposal, and by the middle episodes the pattern has become predictable. Several of the Xs exist mainly to be crushed, which blunts the emotional impact of their stories. The drama also leans on melodramatic turns in its later stretch, and viewers who need a character to root for may find the show’s coldness hard to stay with for 12 episodes.

Who should watch Dear X?

It suits viewers who enjoy dark psychological drama, antiheroines and stories about ambition and manipulation, as well as Kim Yoo-jung’s fans curious to see her in something very different. The 12-episode season is a moderate commitment. It is emphatically for adults: the series deals with child abuse, domestic violence, bullying, suicide and sexual manipulation. More crime dramas are gathered on the same shelf.

Two titles worth pairing with it:

• My Name for another dark Korean thriller led by a woman driven by a violent past.
• My Mister for a far more compassionate portrait of a young woman hardened by abuse and survival.

The verdict

Dear X is a bold, stylish psychological drama, anchored by an impressively icy Kim Yoo-jung and willing to follow a genuinely unpleasant protagonist without flinching. Its repetitive middle and thin supporting characters hold it back, but it is a rewarding watch for anyone drawn to darker Korean television.

Rating: 3.5/5