Star Trek: 12 Biggest Losses Starfleet Ever Faced
6. The Second Battle Of Chin'toka
In the latter days of the Dominion War, Star Trek Deep Space Nine went all in when it came to depicting the horrors of war. The Siege of AR-558 depicted some of the human cost of the war, showing the trauma of the trench warfare that some soldiers were forced to engage, while holding on to the Chin'toka system.
However, The Dominion sought and acquired a new ally: The Breen.
The Breen had dotted the franchise, with early references in the Next Generation. However, they first appeared in Deep Space Nine season four, and their ships appear in the seventh season. They had a devastating technology that drained all of the power from the Federation alliance vessels - including the USS Defiant.
With main power down and no way to restablish it, all shields, weapons and containment fields failed to operate. The crews of every ship in the fleet were forced into the escape pods, being sent home to spread fear with stories of what had happened.