Artei 18th was Imperial Sovereign of the Star Imperium, brother of Artei 19th and uncle of Artei 20th. Of the race of Star Elves, he was born in Year 12,455 on a moon of a gas giant planet in the galaxy And 18, and he served in the military, first in the ranks of the Stormtroopers, later in the Intergalactic Navy.
He noticed the rise in the armed anti-monarchist rebellion of the Rebel Alliance, and his military victories over Rebel Alliance spaceships and ground units caused the Red Monarchists (despite his Monotheism), Blue Monarchists, and the Moderate Party in the Imperial Parliament to strongly unite the Monarchist Party in Parliament and elect Artei 18th Sovereign in Year 12,956.
He denounced the Freethinkers in the Imperial Parliament, the United Planets Assembly (then known as the United Assembly of Stellar Sectors and serving as an advisory assembly), the assemblies of the Stellar sectors, and Subsector assemblies as traitors and seditionists.
His attempts to nationalize the Planetary Security Forces as part of the Imperium's central military forces or the Judicial Forces, to introduce conscription of civilians into the Imperium's military and police forces, and to amend the Fundamental Laws to restrict or eliminate free-speech protections raised vehement opposition in parliament even from some monarchists.
He died in Year 13,001 without any biological or adopted children. After several months of the Council of Twelve exercising the powers of Sovereign with it's regency powers, the Parliament elected his brother as Artei 19th.