Both take place during the Japanese Colonial era and involve the questioning of suspects for anti-Japanese motives - espionage films. One takes place in a mansion house and the other takes place in an isolated hotel. In both films, the Japanese are trying to hunt down a mole called "Phantom". These similarities are because both films are adapted from Mai Jia's 2007 novel, The Message.
Same director and writer with Park So Dam appearing in both films. Both are set during the Japanese colonialism in Korea and have strong female characters. The Silenced is set in a boarding school while Phantom is set in an isolated hotel. The Phantom is an action thriller espionage film while The Silenced is a horror mystery film. LGBT-coded characters in both films. Both show violence towards Koreans and the horrors of Japanese colonialism during the Japanese colonial period in Korea.