X-Men: Messiah Complex (also known as Messiah CompleX) is a comic book crossover storyline published by Marvel Comics from October 2007 to January 2008, which ran through the various X-Men books. The story is the climax of events that began with House of M, which led to the decimation of mutants in the Marvel Universe, and the first chapter of a three-part saga, which continued in Messiah War, released in 2009, and culminated in the Second Coming, a crossover between all X-Men titles in early 2010.