H.A.M.M.E.R. is a fictional espionage and law enforcement agency appearing in American comic books published by Marvel Comics and was formed in "Secret Invasion" #8 to replace S.H.I.E.L.D., created by what two men? 
H.A.M.M.E.R.: H.A.M.M.E.R. is a fictional espionage and law enforcement agency appearing in American comic books published by Marvel Comics. H.A.M.M.E.R.:  The organization is led by Norman Osborn and was formed in "Secret Invasion" #8 to replace S.H.I.E.L.D. The organization plays a large part in Marvel's "Dark Reign" and "Siege" storylines that ran from 2008 - 2010. S.H.I.E.L.D.: S.H.I.E.L.D. is a fictional espionage, special law-enforcement, and counter-terrorism agency appearing in American comic books published by Marvel Comics. S.H.I.E.L.D.:  Created by Stan Lee and Jack Kirby in "Strange Tales" #135 (Aug. 1965), it often deals with paranormal and superhuman threats.
Stan Lee and Jack Kirby