During an early phase of their history known as the Expansion Period, the Stromma engaged in hostilities with the insectoid Quesoth species. The Stromma were defeated and they became firm allies of the Quesoth. Oristrom was later captured by the forces of the alien warlord Nuso Esva, but Esva was eventually driven from the world by Grand Admiral Thrawn and the Empire of the Hand. The liberated Stromma subsequently allied themselves with the Empire of the Hand and some of them entered Imperial service aboard the Star Destroyer Admonitor. However, in 8 ABY, the Stromma envoy Nyama ordered all Stromma aboard the Admonitor to withdraw from the Imperial military and leave the Star Destroyer, because he believed that the Imperials would be defeated during an upcoming attack against Esva's forces on the planet Quethold.
- Crisis of Faith (First appearance)