

Season 1 • Episode 16
LatestMore and more innocent lives are lost as time passes by. The demon has possessed Eun Ho, and she is in dire need of an exorcism. The demon is tempting Soo Min to kill it along with Eun Ho in the name of the greater good. Tough decisions need to be made to exorcize the demon. (Source: Viu)
Oh Soo Min is a former doctor, but he is now a Catholic priest. He performs exorcisms. Meanwhile, Ham Eun Ho is a doctor in the emergency room of a hospital. One day, Oh Soo Min goes to the hospital where Ham Eun Ho works. She gets involved with him.
Acting
Yeon Woo-jin's tortured priest energy is absolutely unhinged
Practical Effects
Demon makeup that will haunt your actual dreams
Writing
ER medical drama meets Vatican conspiracy, somehow works
Trivia, insights & behind the scenes
The 'Mad Dog' keyword refers to Soo Min's nickname in the 634 Regia, a special exorcism unit that operates outside normal Church hierarchy.
The show sparked debate in Korea about its portrayal of Catholicism — some praised its respectful treatment of faith, others found the demon-hunting priests wildly inaccurate to actual Church operations. (The Church has no comment on 634 Regia.)