Doctor X: Mafia in White Episode 10 Ending Explained — Korean Fan Theories
⚠️ Spoiler warning: This post covers the ending of Episode 10.
If you’ve been following SBS’s Doctor X: Mafia in White, you probably know the feeling: the Episode 10 ending left Korean viewers stunned. Days after it aired, Korean online communities and social media are still full of posts trying to piece together one question — who exactly is Kim Seung-hyo, and why do Park Tae-kyung and Jo Won-jin react to him the way they do?
Here’s a rundown of what happened and the fan theories spreading fastest in Korea right now. (If you missed my thoughts on the first half of the series, check out my Doctor X: Mafia in White review of Episodes 1–6.)
What Happened in the Episode 10 Ending
Kim Seung-hyo (Jeon Kuk-hwan) arrives at Guseo University Hospital as a heart transplant patient. He’s the founder of White Wings, the medical volunteer organization Gye Su-jeong (Kim Ji-won) once worked with, and he’s publicly known as a respected humanitarian doctor. He names Jo Won-jin (Lee Jin-hee) as his guardian and Gye Su-jeong as his surgeon.
Then things turn dark. Intern Park Tae-kyung (Kim Woo-seok) tries to smother Kim Seung-hyo with a pillow. Jo Won-jin, his supposed guardian, doesn’t stop him. Su-jeong is the one who steps in — and at that moment, Kim Seung-hyo opens his eyes and greets her with a chilling line: “It’s been a while, Doctor X.”
Theory 1: Kim Seung-hyo Is Jo Won-jin’s Father
This is the most popular theory by far. Sharp-eyed viewers noticed that in a flashback shown in the Episode 11 preview, Jo Won-jin’s doctor’s coat carries a different name: Kim Won-jin. That led to the idea that she changed her name — possibly taking her mother’s surname — to cut ties with her father.
Other clues fans point to: Kim Seung-hyo chose her as his guardian, and some believe the man in her graduation photo is him.
Theory 2: A Family Tragedy Behind Jo Won-jin’s Hatred
If he really is her father, why would she stand by while someone tried to kill him? Fans have offered several versions. One theory suggests a sibling in her graduation photo suffered something terrible because of Kim Seung-hyo, called him “a monster,” and later took her own life — after which their mother was admitted to a care facility. Other viewers suggest long-term domestic abuse instead. None of this has been shown on screen yet.
Theory 3: Park Tae-kyung Was a Victim at Kim Seung-hyo’s Orphanage
The drama has already established that Park Tae-kyung grew up in an orphanage. Many viewers believe Kim Seung-hyo ran that orphanage and that children there were abused — some theories go as far as human trafficking or organ trafficking. In this reading, Tae-kyung didn’t end up at Guseo University Hospital by chance. He came for revenge, and the pillow scene was that revenge in motion.
Theory 4: Were Jo Won-jin and Park Tae-kyung Already Working Together?
The fact that Jo Won-jin didn’t intervene has fans asking whether the two share a hidden past, or whether they simply hate the same man for different reasons.
Theory 5: White Wings Was a Front
The boldest theory connects everything. White Wings may have looked like a humanitarian group, but some viewers believe it hid crimes against children — possibly including an orphanage overseas, with Cuba mentioned in some theories. In this version, Su-jeong discovered the truth, and a fire was set to silence her. This is the most speculative theory of all, built by combining scattered clues.
What’s Confirmed — and What Isn’t
To be clear, everything above is fan speculation, not confirmed by the production team. What the show has confirmed: Kim Seung-hyo and Su-jeong share a past, Park Tae-kyung acts like Kim Seung-hyo is his enemy, and Jo Won-jin’s behavior shows strong hostility toward him.
What to Watch for in Episode 11
Most Korean theories now come down to three questions: Is Kim Seung-hyo really Jo Won-jin’s father? What happened between him and Park Tae-kyung at the orphanage? And what did Su-jeong go through with him in the past — why does he call her “Doctor X”?
Which theory do you believe? Let me know in the comments.
