First, Shin Sung Rok got the limelight when he confirmed his appearance in The Penthouse: War in Life as Joo Dan Tae (played by Uhm Ki Joon). But he had to leave before the filming started due to scheduling issues. Netizens are assuming that itŌĆÖs because he got to play the main role in the drama Kairos, which airs at the same time. Oh Man Seok was reported to have been cast to play Ha Yoon Chul in the drama. But Yoon Jong Hoon replaced him when he exited the production for some reasons (which was not reported). Ha Seok Jin was also reported to have been offered to play a role in the drama.Back in February, he was said to be considering the role of Logan Lee, the only son of the theater owner and a real estate millionaire. However, since Park Eun Seok is currently starring in The Penthouse: War in Life as PE teacher Logan Lee, netizens are wondering if Ha Seok Jin left the drama or if thereŌĆÖs going to be another Logan Lee. Source (1, 2)
