So, more Enemy conspiracy boarding, this time on possible candidates. We know the Enemy can alter reality as it is written, is involved with the Curse of Steel (or invested in not having it broken), and has been feuding for a very long time. In no particular order:
1. The Morrigan. The Enemy can seemingly control reality/fate, which suggests another fate entity might be our big bad. The Hading Witch doesn't like us and was adversarial to Hallr, and might eat babies. However... It doesn't seem to fit. The Norse weren't great friends of the Irish, but did trade with them, and nothing of my admittedly limited knowledge of Irish myth suggests they Morrigan would be able to influence Norse cultivation or have a particular grudge against them more than anyone else in possession of silver and axable flesh at this time. The Greek fates could fill this roll too, but with less personal connection to the story.
2. Hissi, the Wasp. Well, we know that Stigr repeated the myth of his curse of Steel, and the Enemy seems invested in Steel. But Hissi is a pretty faint presence in myth. Hissi is generally a term for a Finnish nature spirit. There's not a lot of weight here. But maybe that's enough freedom for Imperial to work with.
3. Any and all trickster/adversary spirits. Loki/Eris/Satan/Hissi/Set, any or all of the above. Maybe aspects of one being. One of my personal favorite theories, because linking Satan in brings in a connection to Christianity, bringing in something like The Apple explains how the Enemy could fuck with cultivation,and explains some of the fuckery involved with the connection to the Sea Peoples if we assume there is a force that's just Fucking With everyone on a civilizational level. Eris could link the Bronze Age Collapse to the Trojan War, which is so cool as a history/myth concept. Satan also fits the timeframe we have for the Enemy.
4. The Giants. Well duh. We're in a Norse story, giants are baddies. Giants can have powerful magic as well as being quite deadly - Uthgard Loki could probably pull off reality alteration stuff. They were also feuding with the Norse since the creation of the world. My one quibble is that apparently there are Jotun within traveling distance of us. That doesn't exactly scream cosmic fate altering Enemy, it suggests they're more of a D&D monster for purposes of this quest. Then again, maybe there are giants and Giants. Could also be the Greek Titans, the origin stories are clearly cross-pollinated to a degree.
5. Atlantis. The Enemy seems linked to the Sea Peoples, and where else might the Sea Peoples come from but an island? The sinking of an advanced civilization seems more like a thing that the Enemy might have arranged, though. Unless they were hiding their tracks?
6. The Midgard Serpent. The Hading Witch mentioned the Worm. There are a few Worms (ie dragons) in various myths, but none that would have the narrative weight of the Serpent for a Norsequest. But the Serpent is... Kind of just a big snake. Mindbogglingly, impossibly, colossally big, but just a big snake. Reality warping seems outside it's purview. Maybe a connection to the Oroboros, which is another obvious Worm connection, but the Oroboros is a motif, not a.character. Usually. Still, it links the Serpent with time, and time could be linked to reality-warping.
7. Neanderthals. What the fuck are you smoking, KreenWarrior? Well, they could have a grudge against humanity (modern science suggests they kind of interbred as much as they were wiped out, but I can't imagine it was an entirely peaceful process) and are old as balls, and there's the 13th Warrior/Eaters of the Dead connection. There's also an old obscure book series (Orion was the name of the MC) involving a Time War between ascended human "gods" and a Neanderthal trying to change history to prevent humans from becoming the dominant species. There's also a lot of room to play around here as we have no surviving examples of their culture.
Right now, I think the Giants are the most likely; Imperial has implied it'll be obvious in retrospect. But the Neanderthal or Discord theories are personal favorites.
