The Krath were a religious sect origionally birthed under Seto and Allema Keto, the heir's to the throne of the empress teta system. This came about because the two went to Corecant and somehow got in contact with the spirit of Freedon Nadd. HE taught them rudimentary sith power's. Afterwords they converted Ulic Qel-Droma who promply killed Seto and Joined Exar Kun in his bid for power. Exar Kun used his sith amulet to destroy the sould of Freedon Nadd. Allema was killed when she made the entire Cron Drift (a cluster of about 40 stars) go nova at the same time. this wiped out Ossus and Ultimatly caused Exar Kun's downfall because of the ensuing battle between Ulic and Cay Qel-Droma.
With all that said i Summarize it in two sentances. The Krath were destroyed in the Sith War. Their god was Freedon Nadd.
So there....
But a resurrection might be in order to make the plot work