Searxng/Marshals TV show tv TV Why Monica died in the Yellowstone spinoff: The showrunner reveals the real reason behind Kelsey Asbille's character exit in 1923: Marshals. April 20, 2026 AceShowbiz - Yellowstone star Kelsey Asbille was not part of the new Marshals spinoff due to her unavailability, which led to the offscreen death of her character Monica. This significant plot decision was revealed by the Marshals showrunner after the series premiered earlier this year.