The Ghost Wars were a series of military conflicts fought between the Uvodni and their allies against the Malakh in the Horsehead Nebula of Mutter's Spiral.
Origins
The origins of the Wars are unknown, although the Malakh were known for their aggressiveness. Sarah Jane Smith once said that they would start a war against you "just for looking at them".
The Wars began several centuries prior to the 20th century. (SJA: Warriors of Kudlak)
Later Battles
The Uvodni Empire was backed by an alliance of other races, however the Malakh eventually defeated them all during the course of the Wars. Because of this, the Uvodni needed to find some more allies, and fast.
They came upon Earth and found that the native sapient species, the humans, were a good choice as they were naturally aggressive. In the 20th and early 21st century, the Earth missions were controlled by General Uvlavad Kudlak, who was taken from the front lines in 1988 due to injury, and his Mistress, a computer, and their aim was to abduct human children to send off to the battlefields. The mission was carried out under the futuristic war game Combat 3000. (SJA: Warriors of Kudlak)
End of the Wars
In 1998, the Wars ended under a truce between the Uvodni and the Malakh, however the Mistress was not designed to recognise peace and so hid the message from General Kudlak for 10 years until found by Luke Smith after hacking into the computer systems of Kudlak's warship in 2008. Until then, Kudlak continued sending children onto battlefields.
Kudlak was shown the message and, in anger at the new-found knowledge that his Mistress was a computer and that 10 years and many innocent lives had been wasted, destroyed the Mistress. He sent the children on board his ship back down to Earth where they were sent back to their families, and returned to his homeworld to find any surviving children from previous sendings to the battlefields to return them back to Earth also. (SJA: Warriors of Kudlak)