Jeffrey Cobb is an American professional wrestler and former amateur wrestler currently signed to New Japan Pro-Wrestling (NJPW), where he is a member of Unbound Company. During his original NJPW run from 2017 to 2025, Cobb was a member of United Empire and became a one-time NEVER Openweight Champion, one-time NJPW World Television Champion and three-time IWGP Tag Team Champion. He made his G1 Climax debut in 2019 and competed in six editions of the tournament, notably opening the 2021 G1 Climax with eight consecutive victories, a feat unmatched in tournament history. He was ranked No. 23 in the Pro Wrestling Illustrated (PWI) 500 in 2019 and won the Tokyo Sports Best Tag Team Award in 2022 alongside United Empire stablemate Great-O-Khan. Outside of NJPW, Cobb wrestled in Lucha Underground from 2015 to 2018 as the masked Matanza Cueto, during which he held the Lucha Underground Championship. He also competed for Ring of Honor (ROH), winning the ROH Television Championship, and Pro Wrestling Guerrilla (PWG), where he captured the PWG World and World Tag Team Championships and won the 2018 Battle of Los Angeles. As an amateur wrestler, Cobb represented Guam at the 2004 Summer Olympics, serving as the nation's flag bearer and competing in the men's light heavyweight freestyle category before transitioning to professional wrestling in 2009. Cobb signed with World Wrestling Entertainment (WWE) in May 2025 and performed on the SmackDown brand as JC Mateo as a member of The MFTs alongside Solo Sikoa, Tonga Loa, Talla Tonga and Tama Tonga. He departed WWE in 2026 following the expiration of his one-year contract. On August 16, 2026, Cobb returned to NJPW at the G1 Climax 36 final show. Appearing after a match between his former United Empire stablemates and Unbound Company, Cobb confronted United Empire leader Callum Newman before attacking him and joining Unbound Company.