The first known member of the clan was Hego, clan father of Caar Damask. Caar was a member of long standing in the Banking Clan, who, both as a favor to Mals Tonith and in hopes of advancing a career that had stalled and kept him in middle management, became the administrator of Mygeeto and its crystal mines at some point during the 9th century of the Great Peace of the Republic period. Ten years after his arrival on Mygeeto, Damask was manipulated into meeting his future codicil wife by the Sith Lord Darth Tenebrous, also known as the Bith Rugess Nome, who knew that their child would be very strong in the the Force. Tenebrous was correct—their son, the future Dark Lord Hego Damask—named after his grandfather—was born on Mygeeto in due course. When Hego turned five, he was handed over to Nome, who took him as his apprentice and named him Darth Plagueis.
Hego would later found a plasma mining company called Damask Holdings, which the Sith Lord used to further the Sith imperative.
Plagueis claimed, in 65 BBY, that he killed all his relatives, leaving him the sole heir to the Damask fortune.
The Damask family apparently died off in 32 BBY, when Plagueis's apprentice, Darth Sidious, murdered his master in his apartment.