The object slowed in velocity and began a long orbit of the Earth. Radar then picked up 36 smaller objects "breaking off" from the main body. Each of these smaller objects was measured at 15 miles in diamater.

By this point, the President and Joint Chiefs of Staff realized that Earth was about to be visited by an unknown intelligence from deep space. Shortly thereafter, the skies over Russia and Northern Iraq were on fire with what was described as "unusual atmospheric phenomenon". Sightings then began coming forward from the American west coast, and then the phenomenon was sighted in the New York and Washington areas. One AWAC radar plane sent to investigate the object off the California coast was incinerated by the alien vessel's entry in Earth's atmosphere. The massive craft then settled over 36 of the world's major capitals and population centers, including Washington D.C., Los Angeles, New York City, Moscow, London, Paris, New Delhi, Tokyo, Tel Aviv, Berlin, and dozens more. Once the huge "destroyers" were in place, the aliens then proceeded to annihilate the world's major cities.

Humanity's first knowledge of the aliens came from the crash of an alien "attacker"-type ship which crash-landed on July 4, 1947 near Roswell, New Mexico. The craft held three occupants: two died in the crash. The third lived on for 18 days. On the tenth day, the head of research at Area 51, a Dr. Welles, reported that the alien was "reading his mind," according to Dr. Brakish Okun of Area 51. On the eleventh day, the alien made full contact with Welles, and the two had a "conversation" composed entirely of empathic images and feelings. The alien claimed to have peaceful intentions, with no harm meant to humanity. The alien then died a few days later.

Much was learned of the aliens after studying the bodies of those that crashed at Roswell. They are somewhat shorter in stature than an adult human. Sensory perception is much greater: the eyes lack an iris to restrict light, and the aliens possess a peculiarly linked sense of hearing and smell by way of coterminous auditory nerves and olfactory organs. In other words, they can "hear" scents as well as smell them, and "smell" sound.

The alien "mouth" is little more than a slit in the skin beneath the beak. There are no vocal cords, which scientists at Area 51 took to be further evidence of an "extra-sensory" communication ability. It is not known what, if anything, the aliens eat, as there were no remains found in the Roswell aliens' gastrointestinal tracts. However, a set of glands were found that secreted a strongly digestive substance, so it must be assumed that the aliens do digest food in some form or another. Although the alien possesses a circulatory system, it lacks a heart or other pumping organ. Instead, peristaltic motion of the muscles keep blood flowing.

The alien brought to Area 51 by Marine Captain Steven Hiller was encased in this "exo-skeleton", itself believed to be a lifeform specially raised to serve the aliens. Apparently this bio-mechanical suit is an animal raised by the aliens, then slaughtered and gutted, leaving the neuro-musculature intact. The exo-skeleton is a little taller than a human, with eight tentacles protruding from the rear. The entire "armor" seems particularly suited for a wide variety of possible environments and extremes. Inside the "skull" lays the alien itself, burrowed under several layers of the exo-skeleton's bodily tissue.

There is no proper name for the aliens... they have simply been referred to as "the aliens" or "the invaders". From what has been learned from President Whitmore's encounter with the one Captain Hiller captured, the aliens wanted to exterminate Earth's human life so that they could use the world's natural resources for their own use. The aliens have gone from world to world, destroying indigenous life and stripping whole planets bare.

The city-destroying craft of the aliens have been designated "Destroyers". Each one is fifteen miles in diameter. They seem to be designed for the express purpose of destroying areas of dense population in one strike. This is done by an extremely powerful "particle beam"-type weapon fired from the bottom center of the massive craft. Once fired, the energies of the weapon spread out over a large area. The effect is not much unlike that of a high-yield nuclear attack, only without a mushroom cloud or high levels of radioactivity. The ships have also been seen to have offensive weaponry, as noted during the alien attack on "Operation Welcome Wagon". Defensively, the Destroyers are shielded by a technology as yet unknown to Earth science. Missiles fired at the ship only explode on the shield, a safe distance from the hull. The shield is sufficiently strong enough to withstand a direct nuclear attack with no damage.

Besides the Mothership and the Destroyers, the aliens also utilize smaller "Attackers". These were first seen in the Black Knights' attack on the Los Angeles Destroyer. The Attackers each seem to have a crew of one , although one crashed in Roswell, New Mexico in the 1940's and was known to carry three aliens. The Attacker craft are extremely maneuverable and fire a green "laser"-like weapon. Like the Destroyers, the Attackers also have shields. It seems that the shields are keyed to extremely fast-moving objects, as the ship recovered near Roswell would let technicians work over it and would allow a Coke can to be placed on its hull, but would repel a bullet being fired at it.