Georgui Kasaev is a Russian-American actor, stunt performer, and former professional mixed martial artist who has established a specialized niche in Hollywood as a high-intensity character actor. A former trick rider for the Moscow Circus, Kasaev transitioned from a career as a fighter—holding black belts in Tae Kwon Do and Brazilian Jiu-Jitsu—to the film industry, where he has utilized his extensive combat expertise for both acting and stunt choreography. He is perhaps best recognized for his roles in major television productions, including playing a Russian officer in Netflix's Stranger Things and appearing in series such as MacGyver, True Lies, and Leverage: Redemption. In 2025, his visibility increased within the Marvel Cinematic Universe with a credited role as a Russian operative in the blockbuster film Thunderbolts*.