History RememberTheNewGuy / MarvelUniverse

** Baron von Blitzschlag is a minor example, created as a former Nazi supervillain now working as a research scientist for [[ComicBook/AvengersTheInitiative the Initiative]]. He was supposed to have fought several World War II era superheroes, but he was never a particularly notable villain. Blitzshlag was [[WhatCouldHaveBeen originally meant to be Arnim Zola]], but since Creator/EdBrubaker was using the character in ''ComicBook/CaptainAmerica2005'', writer Creator/DanSlott [[CaptainErsatz created a new character to fill the same role.]]

** Baron von Blitzschlag is a minor example, created as a former Nazi supervillain now working as a research scientist for [[ComicBook/AvengersTheInitiative the Initiative]]. He was supposed to have fought several World War II era superheroes, but he was never a particularly notable villain. Blitzshlag was [[WhatCouldHaveBeen originally meant to be Arnim Zola]], but since Creator/EdBrubaker was using the character in ''Captain America'', writer Creator/DanSlott [[CaptainErsatz created a new character to fill the same role.]]

* Parodied (?) with ComicBook/{{Deadpool}} as there have been a number of comics and mini-series that place him in various eras of the Marvel Universe that predate his creation-- teaming up with Iron Fist and Luke Cage during their "Heroes for Hire" era, taking over for Iron Man during the "Demon in a Bottle" era, even showing up in the original ComicBook/{{Secret Wars|1984}} and bonding with the ComicBook/{{Venom}} symbiote. However, it's quite hard to tell which of these stories (if any) have actually happened and which ones are simply {{What If}}s created in the spirit of fun (particularly when you remember that it's already been established that 1) Deadpool's mental instability has been known to mess with his memory and 2) he's aware that he's a comic book character, thus subject to MultipleChoicePast).
* Similarly, Sally Floyd was created for the mini series ''Generation M'', after the events of ''House of M'', with the reader being informed that she had multiple interviews with famous mutants and dated Angel. She was apparently a friend and confidante of X-Men such as Jubilee, Beak and Dani Moonstar, but was simply never seen or mentioned until now.
* Union Jack was another Marvel character from the Silver Age that was retconned into the Golden Age. In fact, an actual Golden Age Marvel hero (the Destroyer) was retconned into being the first Union Jack but in a disguise.

** ''ComicBook/SecretInvasion'' introduced Chrell and X'iv, Xavin's former mentor and classmate, respectively.