Siege is an American comic book, published by Marvel Comics from January to May 2010. It deals with the climax of the "Dark Reign" storyline, which saw Norman Osborn become the United States primary defense officer, leading H.A.M.M.E.R. as well as employing his own evil Avengers. The story depicts Loki manipulating Osborn into leading an all-out assault on Asgard, at the time located within the United States. Captain America and his own Avengers lead a rebellion against Osborn. The events in Siege led to Marvel Comics introducing the subsequent storyline "Heroic Age".

Norman Virgil Osborn is a character appearing in American comic books published by Marvel Comics. Created by writer Stan Lee and artist Steve Ditko, he debuted in The Amazing Spider-Man #14 as the first and best-known incarnation of the Green Goblin. He has since endured as one of the superhero Spider-Man's most prominent villains and is regarded as one of his three archenemies, alongside Doctor Octopus and Venom.