The Wolverine 2 is at least partially inspired by Mark Millar’s Old Man Logan comic, but that doesn’t give us a whole lot to go on, especially when it comes to the villains Hugh Jackman will face in his big farewell to the X-Men franchise. Narcos star Boyd Holbrook was recently cast as an original villain created specifically for the sequel, with Richard E. Grant set to play a mysterious mad scientist. Again, that doesn’t tell us much, but a new rumor may help fill in those blanks.

According to Nerdist, Wolverine is battling Reavers in the upcoming sequel, which — if true — opens up some interesting possibilities. Reavers are a group of lethal militaristic cyborgs bio-engineered by X-Men villain Donald Pierce (who happens to be half-robot himself) to kill mutants. Richard E. Grant’s role is described as a mad scientist, so it’s quite possible that he’s playing Pierce or something similar. More on that in a moment.

Meanwhile, Boyd Holbrook’s mysterious new villain has been described as the “relentless, calculating and intense head of security for a global enterprise.” But what could that global enterprise be?

That’s where we get into spoiler territory for X-Men: Apocalypse – specifically the post-credits scene, so continue reading at your own risk:

That scene takes place in the facility where Wolverine’s bones were fused with adamantium (though it plays out a little differently in this timeline). We see an unknown person pick up a vial of blood marked “Weapon X” and stick it in a briefcase that reads “Essex Corp.,” a reference to Nathaniel Essex, aka X-Men baddie Mister Sinister.

It’s possible that Holbrook’s character is the head of security for Essex Corp., and that Grant is playing Essex / Mister Sinister, a powerful mutant and geneticist who conducted horrific experiments to accelerate the mutation process and tinker with the natural order of evolution. Given the inclusion of the Reavers, The Wolverine 2 could be reimagining Mister Sinister as their creator.

That vial of blood also lends credence to rumors that the sequel will introduce X-23, a female clone of Wolverine. And with Essex experimenting with all this mutant DNA (and possibly building Reavers with it), previous reports that Liev Schreiber’s Sabretooth could return seem a bit more plausible now.

The Wolverine 2 hits theaters on March 3, 2017.