Despite the larger organized criminal networks in Crux, a number of much smaller gangs flitter around as well. Areas like the Grand Bazaar or Poorfellows are unclaimed as turf for the Prince or The Demon's Orphans. These others are small-timers, usually unsorcerous resorting to illegal tactics in order to survive.
These gangs often have a racial or ethnic component to them. Tomasi brotherhoods and sisterhoods with long histories that compete with immigrant gangs from Othebea and Ainesia. They stick to smaller, petty crimes- often protection rackets, gambling, prostitution and theft. These small time gangs also stick to their neighborhoods. They like to claim some sort of benelovence, seeing themselves as protectors of their slums against more impersonal criminals, holding to a street form of honor.
When Ith took control of Crux from Othebea, one aspect of the law they changed was the right of justice. In Othebea and some other states, the Right of Justice grants certain classes and individuals the right to judge and pass legal judgements over others. It used to be a right the Eternal order of the Eagle and the Crow would use to detain and execute criminals, often at the behest of the Archbishop in Crux. These days, Crux follows the laws set down by the Ith government: Citizens get a trial by jury. Otherwise, the law will not protect your interests.
The Sorcerous within Crux do have to obey certain laws themselves. The Agreements outline specific spells, artifice and magic items that are restricted. Any spell known to cause havoc or destruction are outlawed outright. It's hard in practice to enforce, and there isn't a precise listing.
Spells such as Fireball or Earthquake are obvious cases. Other spells are harder to categorize. Animate Dead would seem to be nonviolent, but is illegal in Crux except for use on the corpses of Androids or animals. Any spell the replicates shapeshifting is legal, while Lycanthropic shapeshifting isn't.
Curses are a even more gray case. Despite the auras and other evidence present, most times Curses are perfectly legal. Often Crux punishes criminals through such curses itself. Civil suits can be leveled against the casters of curses, unless they are unsorcerous, but there is no crime on the books for casting a curse that doesn't directly cause property damage.
The right if a trial by jury extends to even the unsorcerous. However, the number of cases that end in their favor tend to be few. Everyone, however, feels the brunt of punishment regardless of Sorcerous ability.
Most criminals serve time on Perdition Hill or they face some sort of curse cast by a court appointed Mage. Curses vary by the scope of the crime. In theory, citizens come have their sorcery stripped from them via such a court appointed curse. In practice, most curses never remove a spell casters ability to spell cast.
Curses will fit the crime. If you crippled a person, your legs are cursed into jelly. If you stole money, you'll be cursed blind. If you are a man who rapes a woman, you are cursed into one and forced into community service for a time.
Of course, the courts of Crux are as corrupt as the City Watch at times. Judges can be bought or sold, and more than few are in the pockets of particular icons, especially the Prince's.