Where the rule of law is seen as being absent, weak, or too oppressive to want, and crime of all kinds flourishes, sooner or later people will take the law into their own hands and become vigilantes. Here are seven such gangs.

They're way over their heads...

"The Circus is in town, Dicurion. Make a donation to the good priests of the Laughing God. See if he won't smile down upon us, and wish our little problem away."

-Olrich van Haarkrom

'The Commonwealth was a terrorist movement of the early 21st century. It used online organization to coordinate its actions against governmental and commercial institutions. The name is an allusion to the…'
- Wikipedia.gov

The Circle of Pharisrak has existed for centuries, it's assassins are considered to be untouchable. Not one has every been seen, let alone sent to justice.

A History of The League of Fox

Blessed enough to enjoy friendly relations with many nobles, some of them very close to the king of Haracon himself, the Guild leaders of the Keepers are the criminal big-wigs every wealthy and famous animal collecter wants to invite to the grand opening of his exotic zoo or animal park.

Many are the pirates who sail the storm-tossed seas, but few are more successful or more feared then the Regulators.

The grey talon assassins are a very special group for one reason. They have never been caught. They are impossibly hard to find; many doubt their very existence. Once one has found them, they can be sure the job will be done... for the right price of course.

The religious assassins known as the revenants are some of the most effective killers in Midian.

First he becomes sweaty and feverish. Then the boils begin. The boils are beautiful. After that, he finds it difficult to breath, then move, then he drowns in his own blood. Is that sufficient?

The Strangler is a chaos entity worshipped by an assassin cult. Using narcotics in their worship members of this killing cult are very very dangerous.

Then all of a sudden, the victim gets convulsions and seizures, eyes bulging and mouth foaming.

The King's Hands are a secret espionage group. These agents secretly support the Crown, feretting out traitors, investigating military and political manuverings of other countries, stealing copies of plans and spells that would unbalance the status quo, and in short, making the world safe for good decent people and the Crown that supports them.

The principal axiom of the Curalon Hestaris, and the basis of all its teachings, is this:

"Inhale. Kill. Exhale."

The Liberators of the Coin is primarily an organization Halflings devoted to (insert trickster/thieving/Halfling god). They pattern themselves after a myth of the god stealing gold coins from his brother on the evening of his wedding. The stolen gold was a part of the wedding ceremony and its absence meant that the ceremony could not proceed. The theft resulted in the trickster being able to marry his brother's intended.