Liam O'Brien

A voice shaping Exandria as Vax'ildan, Caleb Widogast, Orym, and Halandil Fang, while guiding stories through narration and original tales.

Liam Christopher O'Brien (born May 28, 1976) is an American voice actor, writer, and director who serves as a regular cast member of the Dungeons & Dragons actual play series Critical Role. In this series, he portrays player characters including Vax'ildan ('Vax'), Caleb Widogast, Orym, and Halandil Fang. Beyond his on-screen roles, O'Brien is one of the narrators for the audiobook edition of the novel Critical Role: Vox Machina – Kith & Kin (2021). He also authored Critical Role: Der Katzenprinz & Other Zemnian Tales, an in-universe fairy-tale collection released on April 8, 2025. His work with the group helped them raise over $11 million on Kickstarter for their animated series, The Legend of Vox Machina.

Quick Facts

Born

28 May 1976

Birthplace

Weehawken, New Jersey, U.S.

Occupation

Voice actor
writer
director

Years active

2001–present

Spouse

Amy Kincaid (2002)

Children

Lore & Background

O'Brien's contributions to Critical Role are defined by his specific character portrayals rather than world-building duties like a Dungeon Master. He plays Vax'ildan in the main cast, reprising the role for the animated series The Legend of Vox Machina after Amazon Prime Video acquired streaming rights in November 2019. In June 2021, he joined the cast of Exandria Unlimited, playing Orym. His other significant player characters include Caleb Widogast and Halandil Fang. The show itself achieved major milestones, winning the Webby Award and People's Voice in the 'Games (Video Series & Channels)' category at the 2019 Webby Awards. Following this success, the cast left the Geek & Sundry network in early 2019 to establish their own production company, Critical Role Productions.

Reader's Guide

On Critical Role, O'Brien is one of the players, with Matthew Mercer as the Dungeon Master. His primary characters are Vax'ildan ('Vax'), Caleb Widogast, Orym, and Halandil Fang. He reprised his role as Vax in the animated series The Legend of Vox Machina, which originated from a Kickstarter campaign that raised over $11 million. In 2021, he added Orym to his repertoire with the spinoff Exandria Unlimited. His literary contributions include authoring Critical Role: Der Katzenprinz & Other Zemnian Tales (released April 8, 2025) and narrating the audiobook for Critical Role: Vox Machina – Kith & Kin (2021). The group's success led to their departure from Geek & Sundry in early 2019 to form Critical Role Productions.