Casting news broke during the SDCC panel for The Expanse when it was announced that Elizabeth Mitchell (Once Upon a Time, V, Lost) is joining the cast in Season 3. She'll be joining David Strathairn (The Blacklist, Good Night and Good Luck), whose casting was announced earlier this week. Mitchell is playing a recurring character who, according to SYFY, “brings a new, spiritual perspective to the series."
Speculation is that Mitchell might be playing a Methodist pastor called Anna Volovodov, who is introduced in Abaddon’s Gate. But we also know that The Expanse likes to shift things around and that some characters are an amalgam of other characters.
We don't know much about Strathairn other than his role is recurring. The mystery, for now, is who. Any guesses?
Season 3 of The Expanse returns to SYFY in 2018.