The Diamond Cavern is based off the remains of the original town hall, built centuries ago when Valon was freshly colonised by the Ploror Conglomerate. It is not a pretty sight, despite the best efforts of generations of settlers to soften the edges and liven up the dirty-grey stone. It's sombre and unpleasantly akin to a headstone.
Regardless of the morbid architecture, it remains a massive and robust building and it's no wonder that a Mercenary League detachment has seized it for use as a base. What's less expected is the fact that it still seems to be operating as a nightclub: in short, all that has changed is that the private areas of the building are occupied by Mercs instead of gangs. None of the clientele seem particularly fazed by the League presence, and the Leaguers themselves seem quite content to have their own watering hole. Hole being the operative word.
Most of the Leaguers boredly guarding the street are in dark blue armour and sport a stylised "9" on their shoulders: it looks like a skull with its jaw gaping open and one maddened, bloodshot eye. Very subtle and tasteful. They don't stop or obstruct the drone car as it comes to a rest just outside the front entrance, where a gaggle of would-be customers, both regular and League, wait to be admitted by hulking bouncers.
There are already half a dozen of the High Council's distinctive bronze autocabs parked up on the street, or in some cases latched on to the walls of the Cavern's upper stories. As the party watches, one such cab disgorges its robed and regal passengers into the penthouse suite, then disconnects itself from the door and hovers off. The Mercs are entertaining High Councillors this evening, and they must have assumed the party was part of the retinue...