Externals

The Externals are a group of fictional characters. Considered a rare subspecies of mutants, most of them were X-Men antagonists.

Background
All of the Externals were originally portrayed as immortal and important, playing an extremely major role in the future and Apocalypse's rise to power (as expressed by Cable), but eventually most were killed off. Only Selene, a previously established character, was spared from the purge. Saul, Absalom, Gideon, Nicodemus, Burke, and Crule (to a lesser extent) formed the self-fashioned "High Lords", bent on playing power games and manipulating events behind the scenes. Crule was employed as an enforcer and assassin for the other High Lords, while Candra and Selene preferred to play their own schemes separately and didn't take any part on the High Lords gatherings.

At one point, X-Men regular and former New Mutant Cannonball was declared an External by Cable, although Selene denies this, suggesting it was just a ploy by Cable. More recently however, Cannonball was shot three times through the chest by Reverend Stryker's Purifiers, and was back up and around in a matter of hours. When asked about it, Hank McCoy mentioned Sam’s status as an immortal again, though it’s not sure if he was joking or not. Apocalypse has also been referred to as an External on several occasions; his longevity is believed by Selene to be mostly due to technological means, although Apocalypse was already many centuries old before his first encounter with the technology he would later integrate himself with. To note, Selene herself needs to maintain her supply of life force that she drains from human victims.

Each External was claimed to represent an intangible concept:
 * Absalom - despair (killed by Selene after she drained his life force)
 * Burke - fortitude (mentioned to have been killed by the Legacy Virus)
 * Candra - guile (Thought to had been killed when the gem that housed her life-essence was destroyed by Cyclops, her psyche still lives on)
 * Cannonball - hope
 * Crule - ferocity (killed when his life force was drained by Selene)
 * Gideon - opportunity (killed when his life force was drained by Selene)
 * Nicodemus - wisdom (killed by the Legacy Virus)
 * Saul - patience (killed when Selene drained his life force)
 * Selene - corruption (killed at the end of Necrosha when X-Force prevented her from attaining godhood, later resurrected by Arkea)
 * Apocalypse - destruction (Taken away by the Celestials, his current status is unknown)

Candra, Selene, Apocalypse and Cannonball are currently the only Externals alive, although, Apocalypse and Cannonball status as Externals continues to be unclear.

Askani
In (Earth-4935), the Externals were all killed by Apocalypse who ascended to power and gained control of the entire planet up till the 39th century.

Age of Apocalypse
In the alternate reality created when the time traveling Legion killed his own father, it's unknown what happened with the Externals as only a few had made their presence known as soldiers of Apocalypse. Candra, Selene and Gideon were recruited as the first wave of Horsemen of Apocalypse, Cannonball was a member of Sinister's Elite Mutant Force and his status as an External may never been discovered, and there is some speculation that Crule was the mutant known in this reality as Wolverine. Absalom, Burke, Nicodemus and Saul did not make an appearance nor were mentioned, so it is possible that they were killed during Apocalypse's ascension.

X-Men: The Animated Series

 * In the episode "Sanctuary Part 2", Saul and Gideon are seen watching Fabian Cortez announce his scheme to the Earth.
 * In the episode "Externally Yours", Gambit's past involvement with the respective guilds of Thieves and Assassins, as well as with the External Candra (depicted here as an African-American "spirit lady", as opposed to a Caucasian telekinetic, and merely known as "The External") are detailed.