Published between 1999 and 2000, Universe X is a limited series written by Jim Krueger and Alex Ross with art by Doug Braithwaite. It is a sequel to Earth X and part of a trilogy concluding with Paradise X.
The story takes place in an alternate Marvel universe where the world has undergone dramatic changes due to the release of the Terrigen Mists. The series features a large ensemble cast including Captain America, Spider-Man, and the X-Men. Key plot points include the revelation of the true nature of the Celestials.
Universe X consists of 12 main issues and several tie-ins expanding on the narrative established in Earth X.