Tropas te Casas
All of the Casas Crantas (and many of the Casas Menoras) maintain large private armies of well-trained, professional troops.   This custom has its roots both in the paranoia of the Casas, and the Merochasan preference for buying one's way out of any distasteful situation.
From the very beginnings of the city of Merochas, the custom has been that each able-bodied male, from his teens, is responsible for his share of the city's defense.  This responsibility extends beyond the threat of hostile action, to include fire, flood, storm, or other natural disaster.  This custom is currently maintained in name only - the "militias" of citizen soldiers are rarely called upon to do anything more strenuous than help fight a dangerous fire in the city, or to help shore up levies in times of flooding.  Often, the "regular drills" specified by civic law are nothing more than drunken parties of laboring class men, and are treated as almost an informal holiday - an excuse from work.
The wealthy, of course, figured out a way to buy themselves a reprieve from this custom.  It was decided that a man could pay for another to stand in for him at drill.  Since all citizens were required to do so anyway, this meant that an outsider, a foreign mercenary, would have to be recruited for such.  Because such mercenaries were thought to be "unreliable" when compared with the fine citizens of Merochas, it was then decided that two such mercenaries should be recruited in the place of any one citizen.  As time went on, this practice became so commonplace among anyone wealthy enough to afford it, that the practice became institutionalized.  The civic government wanted more than a rag-tag band of wandering sell-swords, and so required that a precio espata, or "sword-price," be paid to the city for any man who did not wish to drill with the militia.  This price was a standard amount, and the total sum (a significant amount of money) was used to acquire the services of "professional" mercenary companies.  Such companies could serve continuously, and thus allowed the citizens to go about their daily business, while the mercenaries provided a form of standing army.
Of course, the city did not want to entrust its defense solely to mercenaries.  The city maintained its own cadre of professional troops as well, the Marinos Civico (Civic Marines).  The Armata (navy) was also Merochasan, recruited from among sailors and citizens seeking more adventure.  But the majority of the Merochasan land forces have been mercenaries for over a century and a half.
Of course, the Casas had to cut their own deal, collectively, with themselves.  They decided that since each male of their household was paying for two such mercenaries, and the requirement was really only that those men show up for "regular drills," that they would pay the precio espata for only one mercenary, and would hire and train their own guards, and provide "regular drills" among their own forces.  Most Casas would have large numbers of such guards anyway (due to their paranoia, and for legitimate reasons as well - guarding their trading vessels, for example).  This custom expanded slightly, applying not only to members of the actual family, but also to servants and laborers in the direct employ of the Casa (sailors are exempt from the precio espata, because they already serve in the naval auxiliary to which every vessel of the Casas belongs).   Thus, the Casas normally pay the precio espata for most of their male dependents and relatives, and use that excuse to maintain large private armies - the tropas te casas.
These troops are actually used in time of war, but most often serve in the interior, patrolling the area around the property of the Casas, or serving aboard the ships of the Casas as marines.  Only occasionally do the tropas te casas see actual battle against enemies of the nation.  They do see their share of fighting, however.  Such troops may assist the Rontaria (River Patrol) in repelling incursions from the Wastes, or they may hunt down bandits raiding from the Wylds along the western border (or in the pay of Jyvelik).  And they see occasional combat against each other, when some disagreement among the Casas blows up into a tiny low-intensity war.  Such conflicts happen every few years, on average, but usually last less than a month before the other Casas grow tired of the strife and force a compromise.