Update on my Dragon Quest Builders shenanigans (spoilers through the main quest part two I guess?):
I'm back in Moonbrooke and I accidentally got stuck into rebuilding the castle walls. I suspect that I'm going to end up with the castle being the three-tier build of this map, but I DON'T CARE because it's been BUGGING ME that the walls were a mess and I didn't have enough space for all of the rooms that I wanted to build. >_> (I unlocked the "build a fancy gate!" quest about ten minutes after I'd finally satisfied myself with how the gate side of the castle looked, so I've got pretty solid grounds for this suspicion. On the plus side: it meant that the NPCs did the bits that I decided were too fiddly for me!)
(... Also the Moonbrooke NPCs are slightly my enemies right now, because NORMALLY when you get a big build quest, the villagers/townfolk/whoever will collect the resources because they understand that it's a thing that they're doing and you're helping with. In Moonbrooke, where everything is made out of marble and it's a BASTARD to get, they decided that nope, I had this, I could totally find and make all of the marble blocks they needed. E N E M I E S.)
I'm starting to think that I might just be very bad at judging where the game puts the boundaries for habitable locations, because in Krumble-dun I assumed that the area that became the second bar was out of bounds and not to built on, and in Moonbrooke the areas that I think are in bounds turn out not to be. Still within the castle walls, but too far out of range for the characters to use! This is awkward when it means that only half of a bedroom can be used, because then I turn around and find people sleeping on the floor spikes that are supposed to damage invaders. :\
In plot-related news: I'm 90% certain that something is on-and-off possessing Malroth, and Malroth knows it. The speech patterns are different (he would literally never refer to anything as a "profane place" even if it had a label saying that's what it was called), his particular flavour of "fuck it" is different... Listen, I'm pretty sure that the reason he told my character to stay behind is that he knew that he was not safe to be around, because this is the only time he's tried to turn her away.
As for the Moonbrooke plot... I tend to wander as far as the game will let me before I do any of the plot, because of who I am as a person, which means that I'd visited Moonahan before it got destroyed, and it... Was always a smoking ruin! Literally the only difference is that now Esther can actually see and respond to me! Between that and the sudden discussions about what happens after you die, I'm starting to think that I'm in the afterlife version of Moonbrooke rather than the real one, and everyone's stuck in an endless war because they're dead. That's probably not the plot, but it would explain all of the people who are like "King? Nah mate, we've not had a king in years. War? There is no war in Ba Sing Se." Soooooooo... Slightly concerning. Would explain why everything's fucky. Would not really lend itself to me stealing people out of this castle to come and live on my island though, which suggests it's not right. But based on previous patterns, the king is definitely going to get dead soon, so there is definitely death in this island's future one way or the other is what I'm saying here.