The Spectrals invaded Rhand in one large cargo carrier. This carrier was heavily armed, and the ability of the small Imperial and RMBK Starfleets in the system to counter it was crippled by the destruction of Rhand's ground-based deep space tracking and communications network. The sabotage, committed by unknown parties, took place shortly before the Spectral vessel entered Rhand's space, and left the system with no interstellar communications or deep space radar. This allowed the Spectrals to operate undetected; they quickly used this advantage to arrange the destruction of both Starfleets.
The ORCA teleporting satellite system was then disabled through the use of huge electromagnetic charges, and a thorough, precise campaign of spatial bombardment followed. There were over 600 strikes, which destroyed all key military installations, deep space centers, starfleet facilities, and high-technology industrial centers. How the Spectrals located Humanity's high-tech facilities with such ease is unknown.
The Spectrals also launched a large number of missiles, each of which contained the VISR virus, which permanently alters a person's mind. This virus was dispersed over wide areas, and affected more than 80% of the population. It was a short lived virus; anyone not exposed in the first month was safe. Its effects, however, were anything but short term. The virus permanently altered the DNA of its victims, causing the creation of mind altering chemicals which short circuit the natural inhibitions against murder and violence. The effect is permanent and hereditary. It does not make the host stupid, but leads to a violent, brutal society incapable of higher technology or cooperation.
Wherever the VISR virus hit, the Spectrals also dropped a large supply of simple weaponry, especially the X7MP1 Machine Pistol. This small weapon was designed specifically for killing humans at short range, and was given to the Vissers to speed the reduction of the human population.