They were extremely xenophobic, considering all other races to be vermin. The Empire utilized them as shipyard workers and technicians during the Galactic Civil War, primarily because of their perfectionist nature and knack for technology. This backfired when the Yevetha took over all the Black 15 shipyards and killed or enslaved all the Imperials during a full retreat. During the events of the New Jedi Order, the Yuuzhan Vong attacked and destroyed the Yevetha at the behest of the Fia, a race from the Koornacht Cluster world of Galantos. So great was the Yevethan disdain for other species that one of the survivors chose to attack and destroy a Chiss clawcraft rather than accept aid.