Ok now that i have had a bit more time to go over what we got on them I think i've got an understanding of whats going on here breaking it down
1. Political power struggle
Maretonia is currently in the middle of a massive political power struggle between the centralists, i.e. the queen and her supporters, and the non-centralists, i.e. the stronger nobles. this struggle is their primary focus at the moment over everything and everyone else. which brings me to 2.
2. both slavery as an institution and our diplomatic relations are being used in 1.
Slavery is a major issue for the maretonians as its a major source of power for the nobility and to a much lesser extent the queen herself. as such the nobles are trying to enforce slavery by any means necessary while the queen is either trying to ignore the problem to focus on other centralization reforms, to not set of/give ammo to the nobility, or put rules to weaken the power slavery gives the nobility. This would explain why she basically tried to ignore us, she didn't want to deal with the problem we have right now.
On top of this our presence is being used politically by both sides, the queen is probably trying to use our existence to put pressure on the nobility to give up more power and the nobility are trying to use us to force the queen to back off, either by using us to justify their power base or something else, which leads to 3.
3. Don't expect war any time soon, do expect lots and lots of raids
The political situation in Maretonia is such that organizing a major war would require one side to cave to/defeat the other, something neither wants to do/cannot do. as such I don't see them declaring war outside of extreme circumstances where they see us as so weak that we are easy pickings or as an existential threat, so far they seem to be leaning to the former rather than the later. As such i fully expect incoming deniable raids along the crystal empire and at sea to gather slaves but, more importantly, to probe our abilities and martial capacity.
Conclusions
If we want to avoid the situation from boiling over we need to put up a universal strong show against raids, both at sea and on land. sea is a lot more deniable so i expect that first however, with the Nyhpon and Cannon Ships i think we have that theater on lock down as the only threat i can see would be weather magic. we just need to keep building ships to contest the area, once we get steam powered ships its over. the far bigger issue is our protectorates land boarder, which is far less defended and far away. while its less deniable i fully expect raids here too and in increasing number as we secure the sea so we need to start militarize our protectorate, starting with a proper knight house, then watch towers. additionally we need trains to the front as soon as possible as the only alternative is boat or marching.
While this is happening we need to play diplomacy and intrigue very carefully. the same political instability thats causing this mess is also to our benefit, if we play our cards right we can put enough pressure on them to, at minimum, leave us alone and more hopefully stop being slaving jerks. avoiding war but preventing them from pushing us around should be the name of the game.