Extracurricular Guest cast, played by Kim Kwang Kyu Episode 1x03: Episode 3 (Apr 29, 2020) Episode 1x04: Episode 4 (Apr 29, 2020) Episode 1x05: Episode 5 (Apr 29, 2020) Episode 1x07: Episode 7 (Apr 29, 2020) Episode 1x08: Episode 8 (Apr 29, 2020) Episode 1x10: Episode 10 (Apr 29, 2020)