Chela Nayss was a Nautolan female who lived at the time of the Eternal Empire conquest.
During the war against Zakuul, Chela's homeworld suffered a bombardment from Arcann's Eternal Fleet as a component of the reprisal bombardments directed against the Alliance. Chela Nayss, along with her people, lacked the necessary time for evacuation, resulting in the deaths of millions due to the orbital bombardment, although Chela managed to survive.
As the rebellion against Zakuul progressed, the Commander of the Alliance atoned for the former Eternal Emperor Arcann's actions and guided him back to the Light side of the Force, integrating him into the Eternal Alliance. Chela Nayss, feeling indignant about the absence of justice for the mass murderer, became a member of the Order of Zildrog, a clandestine organization established by Vinn Atrius with the goal of eliminating the Outlander and dismantling the Eternal Alliance. She accompanied the Order to Nathema, where GEMINI 16 discovered and intended to awaken Zildrog, an ancient Iokath superweapon. However, the GEMINI droid deceived and betrayed many of her comrades, confining them within energy transfer chambers to serve as fuel for Zildrog's reawakening. Chela Nayss was among those who were drained to power Zildrog's activation. Shortly after, the Alliance Commander, together with Lana Beniko and Theron Shan, arrived and destroyed the mechanical entity, causing the entire chamber that housed him and the GEMINI's victims to explode.
Chela Nayss makes an appearance in "The Nathema Conspiracy" flashpoint only if the player chose the Light Side option to spare Senya Tirall during Star Wars: The Old Republic: Knights of the Eternal Throne, which consequently results in saving and redeeming her son Arcann later on. If the player opted for the Dark Side choice and killed both Senya and Arcann, Chela Nayss will not become a member of the Order of Zildrog and will instead be replaced by Zera.