Klessium

Klessium(the City of Storms) is the capital of the Eastern Dominance, which is located at the west edge of the Black Lake. It is known for its fantastic architecture, where even basic structures are constructed in the manner of keeps. It is also infamous for its treatment of skaa, and the nobility halfway around the Empire speak derisively of it. One can imagine the true terror that happens here. Klessium holds the largest pre-Ascension ruins in the world, lying just below the surface. The High Houses maintain large presences in the Undercity--some even producing secondary keeps there. Klessium is one of the capitals of organized crime in the empire, with noble houses funding skaa gangs, committing fraud, and maintaining one of the highest assassination rates in the Empire. It is the nearest capital city to an Ashmount, and the high ash concentration leads to many lightning storms during the year. House Sureau and Tekiel hail from this harrowing place.

The Undercity
Klessium is famous for its undercity, a maze of pre-Ascension ruins that lie just below the surface. Many High Houses build secondary keeps there beneath their aboveground counterparts, from which they conduct their less legitimate operations. The rest of the territory is overrun with violent skaa criminals, meaning that of the nobility, only the most competent of Allomancers or the most desperate of individuals will venture very far at all into its depths.

The Games
Anyone with ties to the underworld in Klessium - which is quite a lot of Klessians - is expected to have some involvement in the Games. Noble houses fund their own teams of skaa criminals, which they then direct to attack other teams to capture territory within the Undercity. The nobles who follow these sorts of things often bet on the Games, with some houses and individuals running massive gambling rings focused exclusively on them. There are, of course, plenty of nobles who like to stare down their nose at these goings-on, but it's far more common for one to sneer at the Games in public and then turn right around and place a bet or three in trusted company.

It goes without saying that skaa Allomancers are strictly forbidden, and the Ministry turns a blind eye to the Games as long as any Allomancers that are found are promptly turned over to the Canton of Inquisition. However, it's not that uncommon for particularly powerful - or particularly desperate - teams to allow a few anyway, or even to sneak some of their own Allomancers into their team's ranks.