When were the X-Men first introduced by Marvel?
X-Men
Many of the X-Men's stories delve into time travel either in the sense of the team traveling through time on a mission, villains traveling through time to alter history, or certain characters traveling from the past or future in order to join the present team. Story arcs and spin-offs that are notable for using this plot device include Days of Future Past, Messiah Complex, All-New X-Men, Messiah War, and Battle of the Atom. Characters who are related to time travel include: Apocalypse, Bishop, Cable, Old Man Logan, Prestige, Hope Summers, Tempus, and Stryfe.[26]