Tarvos Ghull is a pirate infamous the galaxy over. Though well-known for atrocities everywhere from Corellia to Geonosis, he and his band have most recently been noted for their involvement in the destruction of the luxury liner Star Queen.
It seems Ghull had recently come by some extremely valuable information, of particular interest to Imperial Moff Villinand. Not wishing to deal with the Moff directly, Ghull made a deal with Seyl Bion, captain of the Star Queen, who would deliver Ghull's information to Villinand (being himself paid by the Moff), and surrender his vessel (and its crew and passengers) to Ghull's band in exchange.
The arrangement was a double-cross, however, and Ghull and his fleet destroyed the Star Queen in retaliation, retreating shortly afterward to familiar pickings on Negaru IV. However, one of Ghull's vessels, the Ravenstar, was stolen from that world by Damon Aligeri (with its captain, Mir'isha, still aboard). Ghull immediately put the word out that the Ravenstar and Mir'isha must be found.
When some of Tarvos's pirates entered into a skirmish with Mir'isha and her friends on Corellia, Ghull learned from them that the Farghul is traveling with Force-users. Believing that this could be his opportunity to smooth-over relations with the Empire (enabling him to sell them his mysterious information), Tarvos has begun to search for Mir'isha in earnest. The pirate has recently visited Mull Station to enlist the aid of Obar Mull, offering the crimelord the full Imperial reward for the Jedis' capture, wanting for himself only the credit for turning them in.