In June 2018, Theory made his Crash debut losing to Rey Horus.[31] On March 2, 2019, Theory defeated Willie Mack, Bárbaro Cavernario and Sansón to become The Crash Heavyweight Champion.[32] In June 14 2019, Theory made his CMLL debut in a six man tag team match with Volador Jr and Caristico beating Rush Negro Casas and Barbaro Cavernario.