The Twelve

1999

An ancient prophecy names twelve mutants whose combined power Apocalypse needs to achieve ultimate ascension. Apocalypse captures the Twelve (including Cyclops, Xavier, Magneto, and others) and uses their energy to merge himself with the body of Nate Grey. Cyclops sacrifices himself to stop the process, becoming merged with Apocalypse instead. A sprawling late-90s epic that fundamentally changes Cyclops's trajectory.

4 core issues, 4 optional tie-ins/crossovers

The Uncanny X-Men #376

The Twelve prophecy is revealed; Apocalypse begins gathering the chosen mutants

The Uncanny X-Men #377

Apocalypse captures the Twelve and begins the ritual

The X-Men mount a rescue; the ritual reaches its climax

Cyclops merges with Apocalypse to save Nate Grey; the team believes Cyclops is dead

Wolverine's role in the battle against Apocalypse's forces

Cable confronts the legacy of Apocalypse; milestone issue

Cable deals with the aftermath of Cyclops's sacrifice