The Sarkeen War was Man’s first war with a non-human intelligent alien race. On (7)620514 (May 14, 2762), the first waves of the alien forces known as the Sarkeen assailed eighteen different locations along the Perseus Frontier of Human Space. They attacked without warning, killing millions without any distinction to innocent lives, civilian or military. They utilized a highly advanced technology that was superior to what Humanity had, and they came by the millions.
The Sarkeen swept deeply into Japanese and American space, taking territory along the leading edge of the Perseus spiral arm. They bombarded uninhabitable worlds with thermonuclear weapons and utilized non-nuclear conventional forces to fight brutal and grisly campaigns of conquest. The inhabited worlds of Sakura, Piedmont, and Ridgeway in British space were taken, along with Shass in the Independence Territory.
After two years of intense fighting to keep the Sarkeen at bay, the combined allied forces of the United States, the Empire of Japan, and the United Kingdom, and others, conducted a thorough and devestating counter-offensive that seemed to take the Sarkeen off guard. In over a year, the conquered systems were liberated.
On (7)7660226, the Sarkeen began a systematic retreat into the unknown regions beyond the Frontier. By July of that year, all general Sarkeen presence had left the region. There has been no formal negotiations, no dealings with the Sarkeen. There has been no official declaration of war, and no official ending of the war itself.
The Byrids who reside in Human Space believe the Sarkeen to be a biotechnical cult of some kind who exist to improve themselves and their condition through direct biological interventions and alterations.
As of (7)710206, it has been four years since the Sarkeen have left. All the nations of Human Space are wondering if and when the Sarkeen will return, and what their objectives, beyond conquest, really are.