Arnkeep is a castle just shy east of Arn Forest. It's a study, very solid-looking building, housing about a hundred people - cooks, help, soldiers, and those just living there.
The castle has been erected on a small craggy clearning inside Arn Forest, and overlooks the Icespear river on it's southern side (used for shipping). Further south, the ever-impressive vista of the Nether Mountains stretches from end to end; and on the opposite side, the Cold Vale can just be seen nestled in the rising slopes on the way to Adbar.
Arnkeep is the first, last, and only civilised stop for those wanting to brave the desert.
The state of affair is kept under the auspices of both Cassandra - called the High Lady Protector Cassandra by the locals - and Sarade Khorist - with no fancy title yet bestowed. The community is directed with a very fair, but hard rule and no tolerance for outside influence. No complaints have been made heard yet - anywhere.
Although Cassandra could be considered the "public face", Arnkeep is run as a joint venture with equal share in ownership, politics and finance. As it oftentimes is with such things, there are many "trivial" things one side (the Lady Protector) just cannot be bothered with. Thus, on the other side of the same coin, Sarade, also manages the books, the mines, the shipping, and oversees the castle's trade relations in the name of the White Dragon Mercantile Company.
The castle itself is solid stone and marble walls, surrounding half a dozen buildings - a tavern, a smithy, stables, some merchants - and, just as important, garrisons for soldiers. It's walls have been fortified to withstand all but magically supported siege.
There are, at all times, twenty to thirty men and women stationed on the walls and in the keep; some carrying the banners of the White Dragon Merchant House, others wear none except a small golden lapel pin depicting a fiery bird-like creature. They all share a quality of seriousness that speaks of well-paid, well-trained and well-organised professionals; not thugs or simple, street-smart mercenaries.
In good faith, the Redcloaks were offered shelter and a place to station troops, and some Militia stay there on a semi-permanent basis as well. Occasionally, one or two of the travelling rangers find a warm food and bedding, at no cost to themselves.
The castle takes it's name from it's keep - a imposing tower on the eastern side of it's walls, rising well above the trees. Glass-paned windows glint in the sun and can be seen from afar. Wall-sized banners blow in the breeze, showing a intermingling of a fiery bird and a stylised white dragon.
This tower houses a tavern at the bottom - kitchens, storage - as well as provides access to the newly-dug dungeons below. The middle storeys keep safe planning rooms for war and entertaining important guests that are not fit to carry their business in the tavern. Very few are allowed access to the very top, which are private quarters and restricted to trusted servants only.
It is no great secret that beneath the tower, rooms are being dug out - called charmingly "the dungeons" - to house an armoury and .. maybe other things.
Around the castle
Settlers are gathering around the walls - building up houses, farms and homesteads - drawn by both the protection offered and the opportunity for business given.
Despite some dissenting claims of being held under a iron fist, the castle and it's protegees are doing rather well. Little of the mentioned ruling is neccessary in the end - Arnkeep is a comfortable and beautiful place to settle.
Both owners take great interest in supporting all that would dare live on the frontier such, and foster their subject's wellbeing with very invested interest, advice and even coin. Cassandra has even been seen digging irrigation ditches hand in hand with local farmers.
Arnkeep also provides protection to the nearby iron mine, and refines part of that iron into steel with locally-produced charcoal. A small-but-busy logging industry has sprung up, supplying customers with wood and other related building materials.
Nearly all local produce is shipped (on the Icespear) westwards towards the Fork, then sorted and tallied in the trading halls, and from there on sold further on as far as Sundabar.
Originally, it was built by Vashando Carrinsbane, to serve as a secure, bigger base of operations, replacing the simple encampment formerly held within the Arn Forest itself. When most of Carrinsbane's troops moved to aid the Fork against a kobold assault, the keep was quietly annexed by the Black Network, with the reasoning that they had provided Carrinsbane with gold for its construction in the first place. He freely admitted to the fact, yet stated that he had no intention to honour any deals made with Zhentil Keep. Nevertheless, their presence was tolerated for some time, as they kept the road clear, and trade continued to flow. Yet resentment grew as with each passing month, the Networks' patrols came ever closer to the Fork.
After some time, traders travelling past Arnkeep, towards and from the desert, suddenly found themselves under overpowering attacks, as did the patrols from Arnkeep. The Zhentarim was powerless to stop them, and despite their assurances at keeping the traders safe, they lost every single man sent out to deal with the matter. It was no big secret that whoever opposed them was a very competent group of instigators, with considerable arcane powers at their disposal, and word went around that whoever wanted to rise up against the Zhentarim would have their help.
For a while, this continued, as political infighting amgonst the Ruling Council made any official stance difficult to impossible. But, eventually, there were other interested parties that took action.
After the murder of one of the Fork's councilors, apparently by Zhentarim agents, the Harmonium (as directed by Cassandra and Sarade Khorist) quietly hired adventurers and mercenaries, and assaulted the keep under cover of the night. Stories are still told of that day, of dragons and demons exchanging claws and spells while adventurers and zhent soldiers battled beneath.
Either way, the keep was annexed and claimed by the Harmonium, citing contracts and investments by Khorist into the nearby iron mine, and refusing any claim by the Fork itself. Some doubted the claims - nevertheless, none tried to stop them, and the Harmonium remains in control to this day.