"Essex Corp". X-Men: Apocalypse ends on those two words: words that will mean little to most people who haven't delved deeply into the world of the X-Men outside the movies. But they're two words that tease a host of possibilities for what's coming. Here Empire attempts to untangle some of those knots.
Spoilers for X-Men Apocalypse follow, obviously. If you haven't seen it yet, or didn't stay right to the end of the credits, come back later...
X-Men: Apocalypse - post-credits scene
We're in the Weapon X facility in the aftermath of Wolverine's bloody escape. A bespectacled James Malloch (credited as "Mystery Man") walks through the post-carnage corridors and collects a vial of Wolverine's blood marked "Weapon X", which he puts in a briefcase with some other vials containing what appears to be blood of different colours. As he snaps the briefcase shut, we see that it's labelled "Essex Corps". This is a nod to Nathaniel Essex, familiar to Marvel readers as Mister Sinister.
Who is Mister Sinister
He's a major recurring X-Men antagonist, first seen in Uncanny X-Men #221 in 1987, created by Chris Claremont and Mark Silvestri. An almost invincible shapeshifter, telepath, telekinetic, schemer and geneticist, his history was established over the course of his many subsequent appearances. He was a scientist in the 19th Century, responsible for waking Apocalypse from his centuries-long slumber and persuading the monster to grant him immortality.
Dropping his name (or something alluding to it) at the end of X-Men: Apocalypse is, says producer Simon Kinberg, "a nod toward potentially a lot of different movies. Certainly the (third) Wolverine movie is related to what happens at the end, but... he could show up in a host of different X-Men films. Maybe a Gambit movie, maybe another X-Men movie."
How might he feature in what we know so far is coming? Let us count the ways...
X-Men 7
We know hardly anything about where the next core X-Men movie might take us, aside from it's being set in the 1990s, when music was better. But clearly, as a major X-villain Mister Sinister is a strong candidate to go up against the mutants next time. His morphing abilities men he's able to mimic and recreate their powers, so that could be a thing. And his desire to create the "perfect mutant" could tie in to some of the philosophical threads that have been dangling in the film series since the very beginning.
Wolverine 3
Equally plausible is the notion that the vial of Wolverine's blood is going to lead into the creation of his female clone X-23 in the next standalone Wolvie film. X-23, AKA Laura Kinney, has been strongly rumoured as a likely player in Huge Ackman's final stand: created with the same healing factor and adamantium skeleton as Logan and raised in captivity to be an unbeatable assassin before she too escaped Weapon X and went rogue (not meaning Rogue, who's someone else). Wolverine 3, we think, takes place in the future. But if X-23 has the same abilities as Logan then she feasibly also ages at the same glacial rate, meaning her beginning in Apocalypse (if that's what's going on) works just fine.
Gambit
Then again, there's the next X-Men spin-off Gambit, starring Channing Tatum as the ragin' Cajun Remy LeBeau. In the comics, Gambit has at one point been one of Mister Sinister's agents, recruiting Sabretooth and others as Sinister's Marauders. Gambit entered into this deal in exchange for Sinister's services as a geneticist, to cure a mutation that was making Gambit's powers uncontrollable. That could work in the film as a shadow returning from Gambit's past that needs to be dealt with.
Deadpool 2
And there's even - rather complicated, esoteric - scope for a Sinister connection in the next Deadpool film. Mister Sinister, for reasons best known to himself, engineered the birth of brick-shithouse anti-hero Cable (via the parentage of Scott Summers and a clone of Jean Grey, if you want to get into it). And we know that Cable is almost certainly inbound for Deadpool 2, thanks to the Ferris Bueller-riffing final shower scene{
It is, of course, possible that none of the above musing is correct. But then again, maybe all of it's somewhere vaguely near the mark and Mister Sinister could be the overarching villain for an entire new, connected, universe of X-movies. Are we reaching? Time will tell...