Keep in mind that these warriors are organized precisely for raiding, and they're mounted to boot.
As the part heads east, little changes in what Gregorius and the others are finding, save for one important factor: closer to the covenant, the villagers had never seen the Amazons before, and were totally shocked at the sudden, vicious raids. Here, though, the locals have more experience of the group: raids are not something that happens constantly, as a village couldn't survive under those circumstances, but adults, particularly the older ones, can cite a few previous ones.
That's interesting, at least. Do they have any strategies for dealing with them beyond the basic "run and hide"? Did anyone ever escape from being enslaved and make it back to their village (and if so, did that have any information that would be useful)?
Once we've gathered what info we can, we'll continue on east.
[Recovering from COVID that started during vacation here--I missed the notification that your post had come in.]
Different villages have different strategies. Some figure that the less of a fight they put up, the less brutal the Amazons will be. Others try to deter attacks by building obvious defenses, including regular military training: they know they can't hold off a full-scale assault, but they figure if the Amazons anticipate taking significant casualties, they'll pick a softer target.
You have not found anyone who's ever escaped enslavement. There are stories of such a thing occurring, but it would be impossible to judge their veracity.
Magic? Yes, but during a raid in the middle of the night a lot of things are going to appear fantastical.
The question here is really whether or not you're pressing forward right now, and what you're going to do to prepare once you get there. I can certainly cut to the chase and say you arrive with little incident.
He'll take a note of the descriptions of "magic" anyway, and look out for anything that seems to be a consistent feature.
I think the key thing Gregorius probably wants to do on the way is revisit the cave where Tasia was held (assuming that it is near the sea) to make sure it's not still occupied by anyone interesting.
Other than that, yes, press on to the sea. Gregorius will ask Fray to Leap back to the covenant periodically to keep in contact with them, and otherwise scout out to find anything interesting / dangerous local to the group on the ground.
Tracing the path of destruction, you make you way ever eastwards, gradually approaching the Caspian Sea. In this country, Amazon raids are a constant threat--though the damage done by any single raid seems to be limited, probably as a result of the recognition by the Amazons of the foolishness of killing the golden goose.
What you can't figure out, in the end, is exactly where the Amazons come from. It's definitely from around here somewhere, near the western coast of the Caspian, but from where exactly?
Gregorius will pick up an arcane connection to the cave, in case we want to come back to / spy on it later, and also check is it's in sight of any bodies of water (in case the covenant gets Enchantment of the Scrying Pool up and running later). For the same reason, he'll familiarise himself with the relevant bit of the coastline of the Caspian Sea (although finding the island itself would be by far his preferred option).
He'll travel along the coast, trying to get a feel for the geography of the area - are there lots of places where the water is accessible (especially for people on horseback), or at they limited by cliffs / marshes? Are there fishing villages along the coastline? How are the amazons getting their horses from their island to the mainland anyway (assuming that they're not storing them on the mainland to begin with)?
Is there are Fishing villages, do they have any useful information? Do they know where the island is, or have places they don't go?
Meanwhile he'll ask Fray to scout the Sea itself, looking for plausible islands, or failing that signs of regios (although sadly Fray doesn't have Second Sight, so the odds aren't very high here).
He'll pick up a few more arcane connections to potentially useful places.
The northern part of the Caspian is largely surrounded by steppe, similar to the covenant's home--indeed, it's also inhabited by Cuman tribes--this is where you initially arrive by the sea, since it's the easiest route to travel.
Further south, the Caucasus mountains jut up against the sea in a few places, resulting in areas with steep coastlines. That does mean there are areas that are largely uninhabited, which will make a search more difficult. One wrinkle here is that a few years ago, an invader from the east (Genghis) conquered this area, and he's still consolidating his rule. There's an uneasy line of contact between his people and the Cumans, though there was also constant fighting between the Cumans and the previous rulers along the same line.
The locals are aware of the Amazons, and are occasionally raided by them (they especially like to carry off young men), but have no idea where they come from.
Fray's search for a likely island turns up nothing, except...there's one area along the coast constantly filled with mist. It's obviously suspicious, but not something he's going to try to fly through, since it would leave him blind.
Fray has no issue taking the risk of more slowly investigating by water into the mist. He would be nervous and cautious about moving into clearly unnatural mist. Doing so in a fish-ish form such as a dolphin (or shark, otter, or some such, is the sea salt water?) is fine. Looking for a form he would know and also could look out of the water, but not sure if dolphins are a valid choice setting wise.
Effects as MuCo20 with +2 for D; Sun for a form size: 0 or less, so MuCoAn30.
Fray's Mu 21, An/Co 11/13, mMF 11, Int 3 = 46 before rolling, which will be enough to spend a fatigue.
If the form is small he will probably increase its size with his own spell - to make himself a big/huge fish to help with travel speed. And I hope I've got this mostly right, its been a while.
[OOC: CT of 46 won't be enough to reliably spont a level 30 spell due to the division by two, but he's already got a formulaic spell that turns an animal into a fish, so he just needs to do it in two steps by turning himself into an animal first.]
Gregorius will suggest to Fray that he carry an arcane connection back to land on him (probably in his mouth?) in case he needs to Leap back for some reason.
There is (you have to either succeed on an EF 12 concentration roll to simultaneously suppress your Parma and cast, or alternatively penetrate your own Parma) , but Fray learnt "Transformation of the Vicious Beast to the Floundering Fish" as a Touch range spell and has Flexible Formulaic Magic, so he can just make it a Personal range spell and sidestep the issue.