Warning: The following contains major spoilers for X-Men: Legends #2, by Fabian Nicieza, Brett Booth, Adelso Corona, Guru-eFX and VC's Joe Caramagna, on sale now.
X-Men: The Animated Series is one of the most beloved incarnations of Marvel's mutants, and the show's legacy can still very much be felt to this day. That's most certainly the case in X-Men Legends #2, where the comic ends by echoing a memorable cliffhanger from the animated series.
This flashback tale delves into the character Adam X and confirms his connection to the Summers family. The hectic adventure confirms Adam to be Cyclops and Havok's half-brother, as well as an heir to the Shi'ar throne. To simiplfy everyone's life, Adam and everyone present has their memories of his true heritage wiped, and Adam goes to live on a farm, free of obligation. However, the issue ends on an ominous note, as Mister Sinister watches Adam from a video screen from afar, as someone watches him, too.
This ending is very reminiscent of X-Men: The Animated Series' Season 1 finale. By the end of the episode, "The Final Decision," Scott Summers and Jean Grey were enjoying what seemed like a happy ending, looking forward to the married life. However, the final moments of the episode reveal that Sinister is watching the happy couple on a video screen from agar, with dire plans in mind. Throughout the next season, Sinister began acting on his plans to manipulate Cyclops, Jean and the rest of the X-Men.
Both of these ominous endings foreshadow some future machinations on Sinister's part and reflect his obsession with the Summers family. Knowing that Sinister is so fixated on the Summers bloodline, it makes sense that he would keep tabs on Adam as well. The ending to X-Men: Legends #2 is also very fitting of the time period, since the tale essentially takes place at a time when the animated series would've been on the air.
Just like in X-Men: The Animated Series, Sinister was messing with Cyclops in the comics. 1993's X-Men #23, by Fabian Nicieza and Andy Kubert had Sinister hint towards a third Summers brother during a discussion with Cyclops, setting up a mystery that would go unsolved until the introduction of Vulcan and the confirmation of Adam X's status here.
Within the comics and X-Men: The Animated Series, Sinister was lying in wait, manipulating events from afar, but he's not the only person doing that here.
The identity of the person watching Sinister isn't revealed here, but recent X-Men history points to one character who could easily fall into that role. Considering the revelations of House of X #2, by Jonathan Hickman and Pepe Larraz, the mysterious figure observing Sinister could be Moira MacTaggert. Moira has lived nine previous lives as a mutant who can reincarnate into new timelines. With every death in mind, Moira may be manipulating Sinister as a way to preserve the mutant race, especially since Adam X could be quite useful as a potential emperor of the Shi'ar Empire.
With Adam on the Shi'ar throne, mutantkind would thrive across the galaxy. Behind the scenes, Moira could be quietly manipulating Sinister into manipulating Adam. Moira could provide some way for Sinister to restore Adam's memories and direct him towards him on the Shi'ar throne. After several lifetimes of violence and death, Moira would probably be working from afar as a precautionary measure.
While there's no concrete evidence that this mysterious third figure is Moira, the figure's presence here means that someone still knows about Adam X's true lineage, and Mister Sinister does too. While many years have passed within the Marvel Universe since this story occurred, Sinister, Moira and a few other master manipulators are well accustomed to plans that take years to fully come to fruition. And in the same way that X-Men: The Animated Series teased Sinister's plans by putting him behind a video screen, it's likely only a matter of time before the truth about Adam X becomes one of the most important facts in the Marvel Universe.