The Screaming Skulls were a mercenary and smuggling band who would do anything that made money.
In 2494, they were led by Declan Moore and his second-in-command, Jack. They owned a freighter called the Privateer. Under his leadership, they declared they wouldn't hide their identity. They often hung out openly in clubs such as "The Pit".
In 2494 the Screaming Skulls, based out of their freighter, the Privateer, bought stolen crystals from bandit duo Tychus Findlay and Jim Raynor, at a good price. They met at The Pit on the moon of Hermes, orbiting the duo's base of New Sydney. The Skulls then hired the duo to steal port junker logs from Refurbish and Recovery Station 5034, but it was a part of a plot by sadistic bounty hunter Ezekiel Daun to murder them. He failed. The duo escaped and realized the Skulls were part of the plot, but couldn't do anything about it.
By 2502 the Screaming Skulls were facing hard times, needing more ships and suffering from a "personnel crisis". Wendell Carver decided to fix both problems by taking over the Apollo Shipyard at Grissom IV. The crew were mostly killed off or imprisoned.
The station was approached by the damaged General Lee, seeking repairs. The pirates lured them in and captured four of the crew, the War Pigs. The fifth War Pigs, Romy Pyrius, had remained aboard the General Lee in order to satisfy his stims habit. Carver tried to induce the prisoners into joining his force, but they refused.
The pirates who boarded the General Lee were killed by a stim-crazed Pyrius, who then turned the ship's weapons against the shipyard. The chaos enabled the War Pig prisoners to escape. Carver and his assistants Dasch and Mithras fled toward the Cutlass, releasing cybercats to attack the War Pigs, but this gambit failed. Carver wasn't concerned, as he planned to nuke the station once they escaped. However, they were stopped by War Pig Nuura Joss, who shot out a station's window, killing them due to vacuum exposure.
The War Pigs used the other prisoners to repair the General Lee, as well as retrieving the alien artifact from the Cutlass.