#entertainment Characters in a shared universe that a writer wasn't allowed to use, so they had to use someone else
Marvel and DC are shared universes where a character can show up in any book if the story requires it, but there are some limitations. A writer may want to use a character, but that character is currently being used by another writer in a book that has "dibs", the character is deceased at the time or in some status quo that isn't compatible with whatever is planned, there is some kind of legal issue at the time, or the editorial team in charge of that character just plain doesn't want to share, so the writer changes course and uses a similar character instead.
For example, Green Goblin was supposed to be in the Axis event, as seen in promotional material, but the Spider-Man editorial team ended up denying permission because Axis wasn't compatible with the plans for Norman Osborn at the time, so Hobgoblin was used instead.
Kieron Gillen wanted to use Patriot in his Young Aveng