I referenced Melan's upcoming Castle Xyntillan here and wanted to give it its own thread. Castle Xyntillan sounds like a great fit for Hyperborea and Melan's work is always fantastic, so win-win.

"Melan" wrote:

We also wrapped up our Castle Xyntillan campaign, and publishing this dungeon will be my main objective for [2019].

*** SPOILERS AHEAD ***

"Melan in his blog" wrote:

Castle Xyntillan is centred around an eccentric and sinister noble family. The Malévols, a bunch of disreputable degenerates, schemers and outright evildoers, are the masters of a backwater province located somewhere in the French Alps (or anywhere else the GM wants to place it), and some of them still haunt their old family nest... whether alive or dead

Based on what I know now, I'm thinking the Malévols are Hyperboreans and that I will place this ancestral keep somewhere tucked away in those mountains on the north side of Brigands Bay. This location makes it close enough to Khromarium for a low-level crew to reach via boat and some overland travel, but not so convenient as to have already been explored. I'll assume that any petty warlords around the bay either aren't near enough to know of it, stay clear because they're fearful of its haunting or have some sort of dark arrangement with the surviving family members. Should work pretty well!

"Melan over at K&KA" wrote:

I have been meaning to write a post about the recent goings-on in the campaign, but never found the time. There is still this 2016 post, which sets out how Xyntillan came to be, and what I intended to do with it. This was shortly after we started playing - the dungeon has developed since then, although the maps you see are mostly final.

Xyntillan is not a "true" megadungeon, but it gave us about two years of play, not counting the one-offs and convention games, with about 75% explored. Ca. 260 keyed rooms spread out through a main level, various rooftops and upper stories, and underground dungeons. Suggested levels 1 to 6, with tons of henchmen. It is quite a meatgrinder.