The Tharcels were an alien race native to Tharcel Prime and a long time enemy of the Romulan Star Empire. In the mid 21st century the Tharcels fought a long war with the Romulans that ended with them being conquered by the Romulans and their home world made into a fleet yard for the Romulan empire. Unknown to the Romulans a group of Tharcel fled into deep unknown space and settled a new planet as their colony. Two hundred years later in 2266 an invasion force under General Nalbin attacked the Romulans at Tharcel Prime. After the Romulan fleet at Tharcel Prime was wiped out Nalbin attacked Romulus itself but failed after the Romulans received help from a federation ship, the USS Bismarck (NCC-3225-A).