>>532303365
I'm thinking the far left landmass, if it's one on the map already. If you zoom in on the blue patch in the bottom left it even kinda looks like there are ley energy orbs or something like that. There's also weird shipwreck looking marks just off the northeast coast which is kinda peculiar.
They did describe Castora as so hard to get to many don't even believe it exists, which kinda makes it sound like it won't be on our current map.