10. Original SinAlthough its the newest retcon on this list, the impact Original Sin had on several characters back-stories and roles in the Marvel Universe has been tremendous. Pitched as the big Marvel summer event of 2014, Original Sin, penned by Jason Aaron with Mike Deodato on art, received mixed reviews, many of which were luke-warm. The story revolves around the murder of The Watcher, Unta, as the heroes of the Marvel Universe try to uncover the identity of Untas killer. As the story unfolds, we learn the secret origin of the original (white) Nick Fury who was recruited by Howard Stark back in the 1950s to act as a global mercenary of sorts. Secretly along side his work for the US Army and later S.H.I.E.L.D, Fury would gallivant across the universe, brutally assassinating threats to planet Earth. The Marvel Heroes discover that Fury was the one who killed the Watcher in an attempt to gain information about future threats to planet Earth. One of the major complaints about this story is that it retconed Nick Furys character, making him look somewhat like a villain. It also unleashed a whole onslaught of retcons, as multiple tie-ins focused on the various original sins of different Marvel characters. Some of these retcons paved the way for interesting stories, such as Thor loosing his ability to wield Mjolnir. Other changes, like Nick Furys back-story, were flops. Nevertheless, in years to come this will undoubtedly be considered one of the most polarising stories in the Marvel canon.