Gastos Niovi held the rank of colonel within the Galactic Empire. He served Admiral Gaen Drommel on the Executor-class Star Dreadnought known as the Guardian.
Rather than give himself and his crew up to the New Republic, Admiral Drommel intended to fight until death. Niovi determined that Drommel's actions no longer benefited the Empire. Consequently, he eliminated Drommel and took over as acting commander of the Guardian. Leveraging his new authority, Niovi surrendered the Guardian to Captain Volahn of the Equity, representing the Republic.