Kim In-kwon (김인권) is a South Korean actor. He was born on January 20, 1978.

Kim In-kwon plays as Kang Won-seok in Parasyte: The Grey.
Kim In-kwon is the top #1 member of the cast and appears in 6 episodes.

Kwon Hae-hyo (권해효) is a South Korean actor and activist.

Kwon Hae-hyo plays as Kim Chul-min in Parasyte: The Grey.
Kwon Hae-hyo is the top #2 member of the cast and appears in 6 episodes.

Jeon So-nee (Korean: 전소니; born March 20, 1991) is a South Korean actress under Management SOOP. In 2020, she starred in the Korean television series When My Love Blooms alongside Park Jinyoung. Jeon made her acting debut through the independent film Photo in 2014 while attending the Department of Broadcasting Entertainment at Seoul Institute of the Arts. She decided to become an actress when she worked on short films with film majors during college. In January 2018, she was selected as one of the most notable new actresses of 2018 in the 1140th issue of Cine 21. Jeon received attention through her supporting role in Encounter as Park Bo-gum’s friend. She gained her first lead television role through the tvN drama When My Love Blooms in April 2020 alongside Yoo Ji-tae, Lee Bo-young and Park Jinyoung. In July 2020, Jeon was confirmed to star in the Korean remake of Chinese film Soul Mate alongside Kim Da-mi and Byeon Woo-seok. Jeon has also posed for the August 2020 issue of fashion magazine Marie Claire. On December 31, she was confirmed as the female lead of KakaoTV drama Writing Your Fate alongside Ki Do-hoon.

Jeon So-nee plays as Jeong Su-in in Parasyte: The Grey.
Jeon So-nee is the top #3 member of the cast and appears in 6 episodes.

Koo Kyo Hwan, born in Seoul, is a South Korean actor, costume designer, editor, producer, director, and screenwriter. He is managed as an actor by Namoo Actors. He graduated from the Seoul Institute of Arts. Koo made his acting debut in the 2009 South Korean romantic comedy “Castaway on the Moon”. In 2016, Kyo Hwan won Busan International Film Festival for the category “Actor of the Year” for his contribution to "Beaten Black and Blue". In 2017, he won Busan Film Critics Awards, Buil Film Awards for the category “Best New Actor” in “Jane”. In the same year, Kyo Hwan won Chunsa Film Art Awards for the category “Best New Actor” for his work in “Beaten Black and Blue”. In 2018, Kyo Hwan won the Baeksang Arts Awards for the category “Best New Actor – Film” for his work in "Jane".

Koo Kyo-hwan plays as Seol Kang-woo in Parasyte: The Grey.
Koo Kyo-hwan is the top #4 member of the cast and appears in 6 episodes.

Lee Jung-hyun (born February 7, 1980), also known by her occasional stage name Ava, is a South Korean pop singer and actress.

Lee Jung-hyun plays as Choi Jun-kyung in Parasyte: The Grey.
Lee Jung-hyun is the top #5 member of the cast and appears in 6 episodes.