In 1995, the writers of X-Men did something most comics had never done before; they went to another dimension. The event labeled Legion-Quest shows a troubled David Heller going back in time and accidentally killing Charles Xavier. Those events caused an alternate timeline where Apocalypse was able to take over the world without the interference of the X-Men. In this Age, Magneto leads a new, more savage group of X-Men. Thanks to the original 'man out of time' Bishop, the X-Men need to go through a series of extreme measures to fix the timeline and save all of reality. Some good guys are evil, some plots don't make sense, and its the single most 90's thing I ever read.
Writers: Scott Lobdell, Mark Waid, Fabian Nicieza, and Jeph Loeb
Illustrators: Andy Kubert, Tony Daniel, Roger Cruz, and many more.