Marren being the son of the King doesn't really sit too well with what I had in mind for his background so I think i'll pass on that. Also your post is great, it covers near everything that should be placed in the setting. But if we are going airships maybe have a hint that Kantle is building soemthing big, like maybe have some people that have somehow managed to escape the slaughter tell the other islands that Kantle has ways of bypassing the road and still use it's massive armies.