Who is 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. Created by Stan Lee and Jack Kirby in Strange Tales #135 (Aug. 1965), it often deals with paranormal and superhuman threats.

The acronym originally stood for Supreme Headquarters, International Espionage and Law-Enforcement Division. It was changed in 1991 to Strategic Hazard Intervention Espionage Logistics Directorate. Within the various films set in the Marvel Cinematic Universe, as well as multiple animated and live-action television series, the backronym stands for Strategic Homeland Intervention, Enforcement and Logistics Division.
Usually led by Nick Fury as executive director (although he reports to a twelve-member council, whose identities even he does not know), this organization often operates as much as a covert agency as a quasi-military one, initially depicted as affiliated with the United States government. Later, S.H.I.E.L.D. was depicted as under the jurisdiction of the United Nations, with vast technological resources at its disposal, with U.N. General Assembly Resolutions and legislation passed in signatory nations aiding many of their operations.However, S.H.I.E.L.D. has been inconsistently portrayed as under U.S., rather than U.N., control - for instance, in Astonishing X-Men #3, Nick Fury explains S.H.I.E.L.D.'s inaction during an incident of genocide by stating that it did not occur on American soil.