Black Haven was a criminal gang on Kinyen. They begun in 2 BBY, and, albeit a major disruption in their organization in 6 ABY at the hands of a Jedi Master, Vikro, they continued in the shadows for much longer. They were a known associate of the ORS, and were known to trade and work with them.
The criminal organization was founded in 2 BBY by a group of dissidents on Kinyen, who were fed up with the planet's government, hoping to cause mass chaos and destruction, and largely unbalance the economy.
When, in 5 ABY, the Black Haven captured two young boys, Xander Vos and Jysek Talore, they set about using the pair in business dealings and robberies to make sure nothing could be traced back to them. In 6 ABY, however, the pair attempted to escape the same day as a Jedi Master arrived in search of Xander Vos. He destroyed the part of the gang located in that city, along with its leader, and heavily set back the organization.
Prosperity and allegiance
Steadying themselves over the next few decades, the Black Haven gang begun to stretch out into other systems, setting up bases on many other planets. When the Outer Rim Syndicate was formed, they were amongst the many organizations that begun trading and allying themselves with it.
Behind the scenes
Black Haven was created in Destiny Eclipse.
When the ORS was coined by another user of the Rebels forum, user Xander Vos retconned the already existing Black Haven as one of the organizations that aided the ORS.