Cardiothoracic surgeon Oh Yeon-joo’s (Han Hyo-joo) father mysteriously went missing while writing the last chapter of his webtoon “W”. Yeon-joo goes to his office and is shocked to see a scene of the dying Kang Cheol (Lee Jong-suk), the main character of W, on her father’s computer. While reading a note left behind by her father, a hand from the monitor pulled her in. She finds herself on the rooftop of a building next to a bleeding man. She manages to save him and realises that the person she saved was Kang Cheol. She then found out that she can only leave the webtoon based on Kang Cheol’s change in feelings. When that happens, the words ‘to be continued’ will appear and she will teleport back to the real world.
- Lee Jong-suk as Kang Chul
He is JN Global’s co-president, owner of broadcasting channel W in the comic world and an Olympic Gold medalist in Shooting. His set-up in the comic causes him to be calm, laid-back, handsome, and very hardworking. He is a 30-year-old fictional character and the lead character of popular comic series “W”. His family died from an unknown killer, yet Kang Chul was immediately suspected to be the killer due to his Shooting background. After being proved innocent Kang Chul tries to find the murderer and seek revenge. Kang Chul, as seen in the webtoon, is later then stabbed on the rooftop of the hotel he is staying in by the killer. There he meets the mysterious Oh Yeon Joo.
A 30 year old second year resident doctor in the Thoracic Surgery of Myung Sei Hospital. She is the daughter of the comic artist who made the famous webtoon series “W”. When she receives the news of her father being absent for a number of days, she goes to his house to investigate. There, she is pulled into the webtoon. She lives with her mother and aunt but it is seen in the series that she usually spends her nights at the hospital dormitories.
People around Kang Chul
- Jung Yoo-jin as Yoon So-hee
Yoon So Hee’s set up in the webtoon is standing as Kang Chul’s personal assistant and close friend. Her romantic feelings for Kang Chul is hinted subtly through out the series through her actions and behavior around him. She is loved by many fans who adore the pairing of Kang Chul and Yoon So Hee.
- Lee Tae-hwan as Seo Do-Yoon
He is Kang Cheol’s bodyguard. He is a martial arts instructor and a close friend. It is seen in the series that Kang Chul trusts him, and is always loyal to him.
- Park Won-sang as Han Cheol-Ho
Inspector and a member of Congress and also a new democratic party presidential prospect. He is the prosecutor of Kang Chul. 55 years old Han Cheol-ho looks for many opportunities to imprison Kang Chul and take him down. He joins hands with Han Sang woon, but later commits suicide through the drawings of Sung-moo.
- Cha Kwang-soo as Son Hyun-seok
The director of a program in specializing criminal investigation and the general manager of the current channel W. He is 58 years old.
People around Oh Yeon-joo
- Kim Eui-sung as Oh Sung-moo
Yeon-joo’s father and a famous 58 years old artist. Also the creator of the popular webtoon “W”. A failed webtoon artist and divorcee, he gains popularity from “W”. However, he starts to realize bit by bit that his webtoon has gained a life on its own and the characters and all the set-ups have come to life in a different dimension. Realizing this, he starts to notice that his drawings are resisted by the characters and the drawings change on their own sometimes. As a result of all the fuss created, he decides to end Kang Cheol’s life by drowning him in the water, which is resisted by Kang Cheol in the webtoon. He meets Kang Cheol in the webtoon when Kang Cheol was stabbed. At the end of the series, he sacrifices his life and stays in the webtoon world so that his daughter could live happily with Kang Cheol.
- Lee Si-eon as Park Soo-bong
Park Soo-bong is one of Sung-moo’s disciple. A right-hand and junior of Sung-moo and confidant of Yeon Joo, he initially doesn’t believe Yeon-joo’s theories at all, but later accepts everything. He is the only one, apart from the father-daughter duo, in the real world who is aware of the two worlds. He mostly voiced over at the beginning of each episode to inform the audience about the untold part of the webtoon that the readers in the real world are also unaware of.
- Nam Gi-ae as Gil Soo-seon
Yeon-joo’s mother and also owner of a massage-salon.
- Heo Jeong-do as Park Min-soo
Thoracic Surgery’s specialist and teacher of Myung Se Hospital. Also very passionate about “W”.
- Kang Ki-young as Kang Seok-beom
Thoracic Surgery’s second year resident of Myung Se Hospital and Yeon-joo’s friend and roommate.
- Lee Se-rang as Gil Soo-young