Spoilers for Thor #11 by Donny Cates, Nic Klein, Matt Wilson, and Joe Sabino.
The return of an old ally has left Thor in a precarious position, and now his former namesake and old flame Jane Foster might be his only hope. Thor's tenure as king of Asgard has been fraught with tension from the very beginning. His first day on the job was interrupted when Galactus quite literally crashed the party by falling from the sky. This led to a desperate quest concluding with Thor putting himself at odds with some of his closest allies and executing the Devourer of Worlds.
As Mjolnir has grown heavier and heavier, Thor seeks out Donald Blake for guidance, the human host he was bound to in his original run back in the 1960s. However, Blake is no longer the kindly doctor he once was. Odin had set up an imaginary home for Blake to be transported to whenever Thor took over, an idyllic world of peace and sunshine. However, Thor hasn't turned into Blake for many years, and in the meantime, the latter has gone absolutely insane in the fake world Odin created for him. When Thor goes to change places with his former alter-ego, he is trapped in a very different world than he thought he would be. And the Donald Blake that took Thor's place in the real world is a bloodthirsty shade of who he used to be.
With Thor trapped and Blake on the rampage, the Valkyrie and retired God of Thunder Jane Foster is the only person who can save the day. Blake, with the powers of Thor and the World Serpernt, bests the armies of Asgard (including Beta Ray Bill, Volstagg, and Sif) and sends them to a different world with the Bifrost. He then cleans up and immediately returns to Earth to visit Jane Foster for a very tense dinner. At some point between going out with Jane and returning to Earth, he murders another Thor, Roger "Red" Norvell. Jane pieces this together at her day job at a morgue. As she does, Blake is confronted by Throg and Lockjaw.
With Thor trapped in a dark dimension of his father's creation and Asgard's army scattered, it looks as if Valkyrie, Lockjaw, and Throg are all that stand against Blake and his goals. The trio make an odd team, but it won't be the only one Jane will be joining in the near future. It's an appropriate matchup, as Jane first got to know Thor under his Donald Blake persona when they were working together at a hospital. The issue implies that Blake still has feelings for the good Dr. Foster, something sure to add more conflict through the rest of Cates and Klein's Prey story arc.
Jane may also hold the key to beating Blake. When he fought the armies of Asgard, he revealed that he had shares most of Thor's memories. This means he has insights into the martial prowess and status of Thor's foe's and allies, which proves to be incredibly helpful in his fight against everyone from Loki to Sif. However, it is revealed in Thor #11 that he has no memory of Jane's time with the hammer, giving the Valkyrie an advantage against Blake that his previous combatants didn't have.