WARNING: The following contains spoilers for Thor #5 by Donny Cates, Nic Klein, Matt Wilson and VC's Joe Sabino, on sale now.
Ever since the beginning of Donny Cates and Nic Klein's Thor series, the titular superhero has been getting ready for the arrival of the Black Winter. Also known as the Star Plague, this cosmic entity is a destroyer so powerful that it kills entire universes, and according to Galactus, it was coming for the Marvel Universe next. In order to have a chance to destroy it, Thor and Galactus went on a quest to power the Devourer of Worlds like never before. Once Galactus reached his final form, the duo was finally ready to face the Black Winter.
Now, in Thor #5, Galactus and his Herald of Thunder fight an epic cosmic battle against their would-be destroyer. However, the issue brings a double dose of surprises: we learn that what the Winter is really after is not the universe, just Galactus. And perhaps even more disconcerting, it's revealed that there is something even more dangerous than the Star Plague coming for Thor and tangibly changing his future.
In Thor #5, the God of Thunder finds himself in the middle of the Black Winter, facing its torturous creations. The Star Plague toys with Thor, sending constructs of his most dangerous foes to fight him. However, these creations are not meant to kill Thor -- rather, they are used to make a point. The Black Winter sees all, from beginning to end, and it says that it has seen the many deaths of Thor -- whenever he fell throughout the history of the Marvel Universe, only to eventually come back.
What's more, it has seen what was supposed to be his true death: fighting side-by-side with Loki, as a wounded old man, against Gorr the God Butcher. As fans may recall, the Black Winter is describing the events of Jason Aaron and Esad Ribic's King Thor miniseries, which concluded the writer's multi-year arc on Thor in 2019.
But Thor managed to outlive that as well. However, that wasn't supposed to happen, and the Black Winter knows why. "The winds have changed, Thunder God," it says. "Something is slithering through time... Someone is killing your destiny. Breaking your fate."
The warning is vague, but it's loaded with dread. Who could possibly be running around through time, changing the very fate of the God of Thunder? What's even worse is that Thor knows the Black Winter is speaking the truth because he's started to feel the effects of those changes: his hammer is getting heavier, as was first noted in Thor #1. Plus, we've also seen other worrying changes, such as Loki now being able to lift Mjolnir (which may or may not be related to changes in time), and Yggdrasil, the World Tree, starting to rot.
Whatever is out there undoing the timeline of Thor poses an even bigger threat than the Black Winter. And considering that the Black Winter simultaneously takes the form of heavyweights like the Midgard Serpent, Surtur, Mangog and a half-dozen more villains in this issue, that's really saying something.
Although this cosmic giant threatened the entire universe, we now know it has no intention of destroying reality. Still, Thor faces a clear and present danger in whatever is disrupting his timeline. What makes this attacker truly dangerous is that Thor has no idea who or what it is, or where (or when) it could possibly be, and the worst part of it all is that they are already winning.