TMDb/Firefly TV Firefly returns animated with the original crew! Nathan Fillion leads most of the Serenity cast back, but Shepherd Book will be recast. March 24, 2026 AceShowbiz - Firefly is set to return as an animated series, with the original cast mostly reprising their roles, but a key character will be recast. Nathan Fillion, best known for playing Captain Malcolm "Mal" Reynolds, confirmed the news in a recent interview, addressing the upcoming changes in the beloved sci-fi franchise.