Warning: contains spoilers to Taskmaster #5!
In a surprising twist, have been killed by Taskmaster, former SHIELD agent Maria Hill reveals herself to be the mysterious puppet master of the entire series, explaining that she faked her death in order to motivate Black Widow, Taskmaster, and Nick Fury to give her access to the Rubicon Trigger - a doomsday weapon left over from Norman Osborn's former HAMMER regime.
At that time, Norman Osborn (formerly the Green Goblin) had become a worldwide hero thanks to his actions during Secret Invasion, and juggled being the Director of H.A.M.M.E.R, which replaced S.H.I.E.L.D, and being the Iron Patriot for his hand-picked team of Avengers. Unbeknownst to the public, his Avengers were notorious criminals posing as heroes and he was the leader of the Cabal, a group of powerful villains interested in manipulating the world to better suit their agendas. Due to his mental instability and the manipulations of Loki, Norman was provoked into initiating an attack on Asgard, which at that time was floating above American soil. Opposed by the reassembled Avengers in Marvel's Siege event, Norman was defeated and his dark side was exposed for the entire world to see, resulting in his imprisonment and removal from power.
In the Taskmaster series by Jed MacKay and Alessandro Vitti, a relic from Osborn's H.A.M.M.E.R. days called the Rubicon Trigger has been unearthed, with Taskmaster needing to secure access to the weapon in order to prove he's not the one who killed Maria Hill. Having collected the intel he needs, Taskmaster is hunted down by Black Widow, but their fight to the death is interrupted by Hill, very much alive and having faked her death to force Taskmaster to undertake this extreme mission. In a nearby safehouse, Black Widow demands an explanation, and Hill reveals that the Rubicon Trigger is "a doomsday weapon - a literal hammer that Osborn could have held over the world to secure his position," something only prevented by his defeat at the Siege of Asgard.
At the time, the Siege event by writer Brian Michael Bendis and artist Olivier Coipel served as a conclusion to the Dark Reign era, which had seen Osborn seize power, with many of Marvel's heroes subsequently confined to the shadows. Although many praised the story for its artwork, there were heavy criticisms of the story for being all spectacle with no substance, a weak ending to a dark and popular period in Marvel Comics history. Taskmaster #5 subtly redeems the series by suggesting Siege wasn't just a fight Osborn randomly picked and lost, but secretly the heroes' last chance to prevent him from accomplishing total world domination.
Hill reveals the deadly Rubicon Trigger is something no-one has been able to counteract since - the chance to deactivate it only comes from Norman's supernatural redemption over in the Amazing Spider-Man. Had Siege not happened, Norman and his Green Goblin persona would have been fully secure in their power.
While the revelation doesn't erase Siege's flaws, it definitely adds a new layer of perspective that may give it a more nuanced legacy. Osborn's downfall originally felt detached from his reign - an opportunity Marvel's heroes made the most of, but one which came along outside their own efforts to dethrone the villain. With Black Widow's discovery of the hidden truth, the story takes on a last-minute significance, becoming the Avengers' final chance to triumph before Osborn's doomsday weapon came into effect, and enhancing the importance of making this crack in his armor count. It won't change the minds of those who already dismissed Siege, but Black Widow's discovery does retroactively change the context of the event for future readers - something that's often key in the final legacy of major comic-book stories.
