Riesstiu I was a Taiidani admiral during the ancient Hiigaran-Taiidan War. Noted for his brutality and ruthlessness, he was stationed along the Taiidan-Hiigaran border at the time the Hiigarans bombed the original Taiidan Imperial Palace on the planet of Taiidan.
After the Hiigaran Navy was destroyed by the Bentusi, Admiral Riesstiu led the Taiidan fleet on a campaign of genocide across the now defenseless Hiigaran Empire, known as Riesstiu's Revenge. After slaughtering billions, Riesstiu spared the remaining Hiigaran populace only after the entire galactic community cried out for mercy by sending them into the Exile on massive prison ships towards the Outer Rim.
Crowning himself as the new emperor of the Taiidan Empire, Riesstiu rebuilt the Imperial Palace on Hiigara, and helped rebuilt the shattered worlds left in his wake. With the Empire now the largest nation in the galaxy, he turned his attention towards preserving his power. Sometime between crowning himself emperor and his death, Riesstiu sired an heir to the Imperial throne, Riesstiu II.
The Riesstiu line would last until the death of Riesstiu IV the Second at the end of the Homeworld War, where Kushan descendants of the ancient Hiigarans returned to Hiigara and destroyed the emperor's flagship. The Taiidan Rebellion would prevent the line from continuing by destroying the Imperial Gene Banks during the battle, and ended the Riesstiu line forever.