They then proceed to establish bases, using guerrilla tactics to harass the Hierarchy while investigating why the Hierarchy has delayed in using their ultimate weapon 'the Purifier', to utterly eradicate all life on Earth and proceed to strip mine the planet. The Novus (a race of machines who fight the Hierarchy to avenge their fallen creators) arrive just in time to save Washington, D.C. Because the Hierarchy has vast military experience from invading and destroying other planets in the universe, the human race is not able to withstand their forces. Before their landing, observatories and scientists on Earth gave warning of aliens but the human race, as a whole, is not able to organize a unified military front against the alien forces. Universe at War: Earth Assault, begins in the year 2012 when an alien race known as the Hierarchy lands on Earth to strip-mine the planet.
Further, on June 27, 2007, Sega announced that the title would allow cross platform multiplayer through Xbox Live and Games for Windows – Live services.
On May 10, 2007, Sega announced that the title was also in development for the Xbox 360, which was released in 2008. Universe at War: Earth Assault was intended to be the first game in a planned series of games to be called the Universe at War series. Universe at War: Earth Assault is a real-time strategy game, developed by Petroglyph Games and published by Sega.
