Dear X

Kim You-jung

Baek Ah-jin

Kim Young-dae

Yoon Joon-seo

Kim Do-hoon

Kim Jae-oh

Lee Yul-eum

Lim Le-na

Kim Yu-mi

Hwang Ji-seon

Kim Yi-kyeong

Sim Sung-hee

Kim Ji-young

Seo Mi-ri

Hong Bi-ra

Moon Do-hui

Son Kang-gook

An Do-gang

Kim Ji-hoon

Choi Jeong-ho

Ryu Kyeong-hwan

Im Hui-guk

Hong Jong-hyun

Moon Do-hyeok

Kim Il-woo

Hong Su-hyeok

Bae Soo-bin

Baek Seon-gyu

Hwang In-youp

Heo In-gang

Hyun Seo-ha

Seok Hyang-i

Jeon Kuk-hwan

Jun-seo's Grandfather

Lee Woong-jae

Heo In-mo

Kim Min-song

Tattoo Man

Kim Nam-hee

Documentary Host

강이안

Art Teacher

Park Seoung-tae

Heong Gyeong-tae

Shin Mun-sung

Park Dae-ho

Park Seung-wan

Jo Yoo-sik

Lee Seo-an

Lim Sun-ye

Gi So-you

Child Baek Ah-jin

Park Hoo

Child Yoon Jun-seo

Go Seo-hee

Madam Gong

Park Bu-keon

Director Park

Bae Jin-ah

Mrs. Kwak

Jo Hyeon-jin

Sim Sung-hee's Mom

Yoon Joo

Class Teacher

권수연

Yu-bin

신은혜

Ga-yeong

우두연

Ethics Teacher

Baek Sun-ho

Xanadu Coffee customer

Jung Woo

Seol Yeong-uk

Choi Sol-hee

Jae-oh's Aunt

Yoon Hyun-soo

Ryu Ji-hyeok

김세윤

Detective

Lee Seung-jin

Detective

Kim Sang-il

Im Seung-yong

Choi Jae-yoon

Child Kim Jae-ung

Gu Bon-jin

Jae-oh's Father

MIYEON

Host

Kim Kyu-do

CEO of Dio Entertainment

Oh Jae-se

Detective

Ma Jeong-pil

Sim Sung-hee's Dad

Jeong Jong-hoon

Principal

Jeong Eun-ran

Housekeeper

Choi Ji-yeon

Reporter

Park Seong-gyoon

News Editor

Son Gun-woo

Director

Im Yu-ran

Convenience Store Owner

Park Dong-il

Mrs. Kwak's Husband

Seo Chae-han

Class President

Jang Eun-seo

Neighbor

Kim Min-che

Neighbor

Yeo Dae-hyun

Detective

Kim Jae-il

Internal Affairs Officer

Seo Hye-jin

Staff

Lee Dong-kyu

In-gang's Manager

Hong Min-gi

Man 1