WARNING: The following contains spoilers for Guardians of the Galaxy #18, on sale now
The Last Annihilation has been an explosive battle across the galactic section of the Marvel Universe, uniting members of the Guardians of the Galaxy, heroes from Wakanda, and agents of Krakoa all in one massive battle against a major Marvel threat. But along the way, some serious villains cemented their own alliances.
One of the surprise winners of Last Annihilation is Sister Talionis in Guardians of the Galaxy #18 by Al Ewing, Juan Frigeri, Federico Blee, and VC's Cory Petit, the Skrull Priestess who helped set off the event and was secretly working with an entirely different villain all along -- and in the process, earned her own fearsome army that's appeared in the Marvel Cinematic Universe to try and accomplish her mission.
At the onset of Last Annihilation, the Guardians of the Galaxy were investigating a remote world known as the Cauldron, which had become a makeshift home for the Brethern of the Forgotten Flame. There, they witness the resurgence of an ancient Skrull belief system centering around mystical forces. Led on by their priestess Sister Talionis, the assembled crowd sacrificed themselves in a bid to empower the nearby Ego the Living Planet -- allowing it to be transformed into the host for Dormammu. The danger posed to all of creation was paramount, but luckily the cosmic heroes of the Marvel Universe were able to unite and ultimately find a way to not just defeat him but banish him back to the Dark Dimension (and seemingly kill Ego in the process).
It appeared as if this was the plan all along, however, with Sister Talionis now setting herself up as a dark counter to Emperor Hulking of the Kree/Skrull Alliance. In the aftermath of the universal battle against Dormamu, it turns out she had an ulterior motive all along: working with Doctor Doom. He's been consistently helping the Guardians (albeit with a cruel edge to his "generosity"), and proves to be a crucial player in Dormammu's ultimate defeat by cutting off his magical reserves of power just as the other Guardians made their move. After the fight is won, Doom speaks with Sister Talionis on the home world of the Chitauri, where the final spell had been completed, and Doom proclaims her the new queen of the alien armada.
The Chitauri as they exist now is largely inspired by their MCU incarnation from Avengers, a powerful army that could give a good leader a major advantage in cosmic battles. It turns out Talinois had always been working with Doom, and that the long game had always been to summon Dormammu (accomplished by Talionis manipulating masses of rebellious Skrulls into charging his return) so that Doom could steal that mystical power for himself. In exchange, he sees Talionis and her new army as allies for future goals -- and the pair agree to reconvene after they've both accomplished their true mission of conquering their respective species.
This sets up Talionis as a genuine threat to peace in the galaxy and indicates that she's far more of a cunning foe than she may have initially appeared. By cementing her alliance with Doom, she's set herself up to become a more dangerous figure in the future of the Marvel Universe. And with the Chitauri army at her back, she could become a genuine threat to the peace brought on by the Kree/Skrull Alliance. Although she'll have the full Guardians of the Galaxy to contend with, it's clear Talionis can be patient -- and might be so again.