The irradiated world of Fallout is about to get even more unpredictable. Ahead of its Season 2 premiere on Prime Video on December 16, the hit post-apocalyptic drama has revealed several high-profile additions to its cast, expanding the series’ already rich universe with new faces, factions, and mysteries.
Based on the popular video game franchise, Fallout takes place more than 200 years after nuclear war devastated Earth. Season 1 followed Lucy (Ella Purnell), a sheltered Vault dweller, and The Ghoul (Walton Goggins), a hardened bounty hunter, as their paths collided in the dangerous Los Angeles wasteland. Season 2 will see that journey continue—this time toward New Vegas—with new characters who could shift the balance of power.
Justin Theroux Joins as Mr. House
Justin Theroux steps into the role of Robert “Mr. House”, the powerful and enigmatic CEO of RobCo Industries. The character was briefly portrayed in Season 1, but Theroux now fully embodies the figure many believe played a central role in the world’s destruction.
Theroux has described Mr. House as complex rather than purely villainous, noting that the character believes he is saving humanity—even if his methods are deeply flawed. Best known for The Leftovers and Mulholland Drive, Theroux reunites onscreen with longtime friend Walton Goggins, promising charged scenes between Mr. House and The Ghoul.
Macaulay Culkin Enters the Wasteland
Macaulay Culkin joins the series in a recurring role as a member of Caesar’s Legion, one of the most feared factions in the Fallout universe. Modeled loosely after the Roman Empire, the Legion is known for brutality and rigid ideology.
Culkin has described his character as a “crazy genius-type” and revealed he is a longtime fan of Fallout lore. Though best known for Home Alone, Culkin has steadily built an eclectic adult career, including roles in American Horror Story and The Righteous Gemstones. His Legion role is expected to bring an unpredictable edge to Season 2.
Kumail Nanjiani Joins the Brotherhood of Steel
Fans first spotted Kumail Nanjiani in the Season 2 trailer, confirming his casting as a member of the Brotherhood of Steel. The secretive organization is devoted to preserving pre-war technology, often clashing with other factions over control of powerful artifacts.
Nanjiani has shared that he nearly joined Fallout in Season 1 but was sidelined by scheduling conflicts. A fan of the show, he personally reached out to the creators and was later offered a role he called “really, really exciting.” Known for Silicon Valley and The Big Sick, Nanjiani brings both gravitas and wit to the Brotherhood.
Rachel Marsh Appears as Claudia
Rachel Marsh rounds out the new additions, playing a character named Claudia. While Prime Video has not formally announced her role, Marsh attended the Season 2 premiere and confirmed her involvement on social media.
Marsh is known for her work on The Morning Show, Unstable, and Adults, and she has an upcoming role in the adaptation of The Love Hypothesis. Details about Claudia remain tightly guarded.
What to Expect in Season 2
With returning stars Ella Purnell and Walton Goggins leading the charge, and new characters representing major Fallout factions, Season 2 is poised to deepen the show’s mythology. As alliances form and dangers multiply, the wasteland is about to become even more volatile.
