Rex Strickland was part of a group of soldiers who bonded with alien symbiotes. They were later recruited by the government to serve as supersoldiers and be the first official members of the Sym-Soldier program. He eventually left the program and became a member of S.H.I.E.L.D.
Rex Strickland was created by Donny Cates and Ryan Stegman and first appeared in Venom Vol.4 issue 1 (2018).
Major Story Arcs
However, after the collapse of S.H.I.E.L.D. he needed Agent Venom's help because his former allies lost control and became completely bonded with their symbiotes; because of this, the U.S. government was going to dispose of them. He sought out Flash Thompson's help, but ran into Eddie Brock instead. Strickland offered Brock more knowledge of symbiote history and capabilities in exchange for help finding his former allies.