Walkers in Darkess divided its activities between smuggling operations and Syndicate criminal activies, such as slicing, extortion, bribery, "protection" and strong-arming.
The Black Sun experienced a split between Klugga and Tesserian over the focus of the Syndicate, with Klugga pushing the Syndicate to become more powerful in the galactic south, while Tesserian has increasingly aligned the Black Sun with anti-imperial forces in the galactic north, along trade lines running from Ord Mantell to Mon Calamari and encompassing the Perlemian Trade route.
Klugga launched an initiative called The Dark Trade Federation, ambitiously aiming to control all galactic trade and criminal activity, while Captain Tesserian worked to divert food and fuel supplies from Coruscant through a series of trade deals, and by supporting piracy and commerce raiders.
The Walkers in Darkness eventually disbanded when Cayce left the syndicate to serve her people, the Mandalorians, and Klugga apparently passed on, having died in his home of publicly unknown causes.
Something of note is that while the Walkers in Darkness family engaged in any number of criminal enterprises, they never engaged in slavery, and Cayce was hailed during her time as the ruler of Nar Shaddaa as the liberator of the slaves, having sent her enforcers to burn out the hives and lairs of those who refused to comply with her demands.