Main •
Park Bo-young as Do Bong-soon • Shin Bi as young Do Bong-soon :A young woman born with superhuman strength who tries not to use her powers but does not hesitate to use them for good when needed. She has had a crush on Guk-doo for a long time but eventually falls for Min-hyuk. She will lose her powers if she harms an innocent with them. •
Park Hyung-sik as Ahn Min-hyuk •
Choi Seung-hoon as young Ahn Min-hyuk :A
chaebol heir and CEO of a video game company who hides his pain underneath his cheeky demeanour. He knows Bong-soon even before the "Bus incident" but is not aware of it until much later. •
Ji Soo as In Guk-doo •
Choi Min-young as young In Guk-doo : An idealistic rookie detective who is passionate about justice. Known for being crazy and extremely aggressive, he is continuously transferred from one department to another. He was initially unaware of Bong-soon's powers.
Supporting People around Do Bong-soon •
Ahn Woo-yeon as Do Bong-ki • Lee Hyo-dan as young Do Bong-ki :Bong-soon's twin brother. He cares for Bong-soon. •
Shim Hye-jin as Hwang Jin-yi :Bong-soon's mother. She corners Bong-soon and always prioritises Bong-ki. She often assaults her husband. •
Yoo Jae-myung as Do Chil-goo :Bong-soon's father. He is naive and cares deeply for both his children. Despite being beaten by his wife frequently, he tries to maintain a positive attitude. • Park Bo-mi as Na Kyung-shim :Bong-soon's best friend from Busan. She was Kim Jang-hyun's fourth kidnapping victim. She knows about Bong-soon's powers. • Baek Soo-ryun as Lady Soon-shim :Bong-soon's maternal grandmother. • Kim Mi-hee as Myung-soo's mother • Kim Soo-yeon as Jae-soon's mother
People around Ahn Min-hyuk •
Jeon Seok-ho as Secretary Gong :Min-hyuk's secretary. • Han Jung-kook as Ahn Chul-do :Min-hyuk's father, Chairman of Ohsung Group. •
Kim Sung-bum as Ahn Dong-ha :Min-hyuk's half-brother. • Shim Hoon-gi as Ahn Dong-suk :Min-hyuk's formerly trusted half-brother. • Lee Se-wook as Ahn Kyung-hwan :Min-hyuk's half-brother.
People around In Guk-doo •
Seol In-ah as Jo Hee-ji :Guk-doo's girlfriend. • Yoon Ye-hee as Jung Mi-hwa :Guk-doo's mother.
People at Baek Tak Party •
Im Won-hee as Baek Soo-tak •
Kim Min-kyo as Ahgari •
Kim Won-hae as Kim Kwang-bok • Kim Ki-moo as Hwang Hyun-dong • Lee Ho-cheol
Do Bong Police Station Criminal Team 3 • Choi Moo-in as Team Leader Yook • Oh Soon-tae as Bulgom (Brown Bear) • Joo Ho as Neokboi (Knock Boy) • Choi Hyung as Heollaengyi (Hell Angel) • Kim Won-suk as Dotbogi (Magnifying Glass)
Ainsoft Employee •
Kim Won-hae as Oh Dol-ppyeo :Head of Development Planning Team;
doppelgänger of Kim Kwang-bok.
Extended •
Jang Mi-kwan as Kim Jang-hyun :A criminal. He was the true perpetrator of the serial kidnapping of young women, and throughout the series, especially the latter part, he was in an enmity with Bong-soon and tried ways to get rid of her. Eventually, Kim Jang-hyun was arrested and sentenced to
life imprisonment for murder and kidnapping. • Son Hyo-eun as Jung Hyang-sook :A murder victim. She was, in fact, Kim Jang-hyun's first intended kidnapping victim but was murdered by him due to her fierce attempts at self-defence. • Choi Hyun-seo as Kim Ji-won :High-school teacher; the first kidnapped victim. • Choi Young-shin as Lee Joo-young :Dance instructor; the second kidnapped victim. •
Min Ji-hyun as Pharmacist :The third kidnapped victim. •
Kim Hyun-mok as Bullied student • Kim Young-choon as Il Jin :A high school student and the leader of Bong-soon's lackeys. •
Yoo In-soo as Kang Goo :One of Bong-soon's lackeys. •
Choi Won-myeong as Jang Kyung-tae • Hong Ye-ri as Ho Soon-yi :Do Bong Walnut shop employee. • Kim Tae-soo as Oh Hyun-joong :The contract killer. • Lee Ho-chul as Team Leader Jo :Oh Hyun-joong's associate. • Hapkie as Member of Baek Tak Party •
Kim Won-jun as Subway Molester • Lee Jung-kwi as a High school boy bullied by Il Jin's gang • Jun Byung-chul as Lee Woo-jin
Special appearances • Kang Ji-young as JTVC announcer (Ep. 2, 8, 10 & 13) • as Fortuneteller (Ep. 4 & 7) • •
Song Won-geun as Song Won-geun, Theatre actor (Ep. 7 & 8) •
Yoon Sang-hyun as Charles Go (Ep. 8) • as Voice Phishing specialist • as Voice Phishing specialist •
Jang Sung-kyu as JTVC announcer •
Kwon Hyuk-soo as fake Indian Monk Nizamuddin / Jo Dal-bong (Ep. 12–14) •
Lee Sang as the Ainsoft Receptionist (Ep. 14) •
Clara Lee as Lee Bong-soon, Dental Hygienist (Ep. 16) ==Production==