Unlike typical fan fiction, which generally remains within the boundaries of the canon set out by the source material, alternative universe fan fiction writers explore the possibilities of pivotal changes made to characters' history, motivations, or environment, often combining material from multiple sources for inspiration.
Fiction using real characters and borrowing from the 19th century include Edison's Conquest of Mars and Sherlock Holmes versus Jack the Ripper.
Among some fans of the 2010s game Undertale, 'UnderSwap' is the common name for an AU in which all the characters' personalities are swapped with what the fandom believes to be their opposite.
This genre of fan fiction is distinct from plot switch in the fact that it usually involves characters from at least two separate series interacting with one another.
[3] Alternative Universes in fan fiction can provide a platform for writers to explore different ways of accurately representing their favorite characters.
This allows the writers of these fan fictions to deviate from the source material in ways that challenge the existing storylines and highlight underrepresented voices.
(TV series) show that is part of the Marvel Cinematic Universe explore these different representations in multiple ways.