I know that's a lot of posting, and I know I added some ancient Greek and Roman political functions in there; lictors, tyrannicide, easily petitioned government and so forth. Dara's Guardians have authority, but it is tempered with the ambiguity of institutions, like the lictors, providing to fail succor if they're screwups or tyrants, as well as the people attacking them...or defending them.
There probably is a city watch, and I have not fleshed them out. Perhaps you guys might want to. Such a group might decide it's not in their best interests to defend guardians from being taken out. That wasn't, however, the case here and wholesale purges are rare.