The X-Men line's upcoming 'Dawn of X' era crossover 'X of Swords' will bring some whole new elements to Marvel's mutant mythos – but it'll bring back some classic X-Men characters that have had a tumultuous history since their '90s debut: the Externals.
A just-released teaser for August 19's Excalibur #11 shows several of the Externals – in this case from left to right: an unidentified person in a nun's habit, Nicodemus, Crule, Apocalypse, and Saul – or as they call themselves in the teaser, "the High Lords."
So who the heck are the Externals? Well, it's a little complicated – like many '90s X-Men stories the concept of the Externals and the story that was ultimately told differ somewhat, with a long and winding path in their development. But the basic idea is, they're mutants who are immortal, and who are foretold play a role in the rise of Apocalypse in Cable's future timeline. They'll also apparently play a role in 'X of Swords, in which Apocalypse may or may not be enacting a millennia-old secret plan for… who knows.
Marvel's teaser is accompanied by text which reads "The High Lords. The attack on Starlight Citadel." Starlight Citadel is, of course, the seat of power of the Otherworld, a magical dimension that provides the source of Captain Britain's power and which has played a central role in Excalibur so far.
Excalibur #11 is labeled 'The Road to X of Swords,' branding which presages the start of the crossover, which officially begins in September 16's Excalibur #12, one of two "prelude" issues for 'X of Swords.'