X-Men: Days of Future Past is fiction.
Marvel Comics . Most of Marvel 's fictional characters operate in a single reality known as the Marvel Universe , with locations that mirror real-life cities . Superhero film . These films typically feature action , adventure , fantasy and/or science fiction elements , with the first film of a particular character often including a focus on the origin of his or her special powers and his or her first confrontation with his or her most famous supervillain or archenemy . X-Men : Days of Future Past is a 2014 American superhero film based on the fictional X-Men characters that appear in Marvel Comics .