The series will also star Mari Yamamoto (Pachinko) and Anders Holm (Workaholics) will have a recurring role. Also part of the show's cast are:
- Anna Sawai (F9) as Cate, a former school teacher and a G-Day survivor
- Ren Watabe (461 Days of Bento) as Kentaro, an intelligent, creative and curious young man who has yet to find his own path
- Kiersey Clemons (The Flash) as May, an American ex-part with roguish exterior
- Joe Tippett (Mare of Easttown) as Tim, an office worker who dreams of secret agent adventure
- Elisa Lasowski (Versailles) as Duvall, an expert operative who has an unwavering confidence in herself and her skills
The series is co-developed by Chris Black (Star Trek: Enterprise) and Matt Fraction (Hawkeye). Matt Shakman (WandaVision) will serve as the show's co-executive producer alongside Black and Fraction, and will also direct the show's first two episodes. Also serving as executive producers are: Jody Harold (Obi-Wan Kenobi), Tory Tunnell (Underground), Andy Goddard (Downton Abbey), Brad Van Arragon (Yellowjackets), and Andrew Colville (Star Trek: Discovery). Hiro Matsuoka (Godzilla: King of the Monsters) and Takemasa Arita (Godzilla: Planet of the Monsters) will serve as executive producers on behalf of Toho Co., Ltd.
Monarch: Legacy of Monsters will have a total of 10 episodes and is set to premiere on November 17th, exclusively on Apple TV+. The first two episodes of the series will debut first with later episodes every Friday.