Federation-Der'kal War

"This is your first and only warning, your last chance for salvation. We come to you not as missionaries of any false gods, nor as liberators from them. We come to wipe your pathetic kind, like the scourge you are, from the face of the galaxy, to kill and slaughter until none remain. We are the Der'kal, and this is the beginning of your end..."

- Der'kal commander; at first contact between his people and the Federation

The Der'kal Invasion, also referred to as the Der'kal War, was the single-deadliest conflict in the history of the United Federation of Planets,