Sephani reigned as the Mosciive Empress on the Inner Rim planet of Simocadia. She was the mother of Prince Yojan and maintained a close friendship with Jedi Master Mace Windu.
Simocadia became a battleground during the Clone Wars between the Galactic Republic and the Confederacy of Independent Systems, despite the Empress's desire for neutrality. Yojan, her son, aligned himself with the CIS and exploited the planet's resources to awaken the colossal Ardana Shadex and obliterate the agrocite mines. His goal was to deter both factions in the Clone Wars from further interest in Simocadia. Despite Mace Windu's rescue of the Empress from a Separatist Droid Army, she declined to assist him in any actions against her son. Windu proceeded to confront the prince, and Yojan chose to activate the Ardana Shadex. However, the Jedi inadvertently destroyed the glass key, which served as its control module. Consequently, the awakened giant not only demolished the mine but also threatened to level the city. Windu, Yojan, and Demo made their escape aboard a Neimoidian Sheathipede-class transport shuttle. Uniting their efforts against the common enemy, they succeeded in destroying the giant, but Yojan paid the ultimate price with his life.