From Halopedia, the Halo wiki
Gideon Emery (born September 12, 1972) is a British actor and voice artist, best known for his role as Deucalion in Teen Wolf.
Emery provided the voice of Jerome-092 in Halo Wars' Blur Studios-made cutscenes. In Halo 5: Guardians Emery voices rampant AI Governer Sloan. Emery provides the voice, likeness, and motion capture performance for Captain James Cutter in Halo Wars 2, and portrays Cutter in the War of Wits live-action trailers.
Emery as Captain Cutter in War of Wits: The Armrest.