Cagewrights

The Cagewrights are a group of unknown malevolent purpose. Their symbol may be a black birdcage. The Striders of Fharlanghn came to the Cauldron Region specifically to investigate the Cagewrights.

The Cagewrights are associated with the prison plane of Carceri. The group was founded by demodands several centuries ago. They wanted to link Carceri with the Prime Material Plane to estable a "gate+town". The demodands are slavers.

Source
The Shackled City Adventure Path - review