Second Battle of Chin'toka

The Second Battle of Chin'toka marked the entry of the Breen Confederacy into the Dominion War in late 2375, in an attack against the Chin'toka system, a territory of the Cardassian Union held by the forces of the Federation, the Klingon Empire, and the Romulan Star Empire. The battle was a major tactical defeat for the allies — and perhaps one of the most lopsided victories of the entire war, thanks to the use of the devastating and previously-unknown Breen energy dampening weapon. (DS9 "The Changing Face of Evil")

Prelude
Although the Federation had previous contact with the Breen, for at least the last decade, very little solid information was known about them. Isolated behind their full-body refrigeration suits, they remained shrouded in mystery, a mystery that was only enhanced by their isolationist policies. As a result, the Federation and its allies considered the Breen to be little more than a minor regional power.

In the second half of 2375, the Dominion was faced with the prospect of the war in the Alpha Quadrant dragging on for several more years — their original plans projected their invasion of the Federation and the Klingon Empire to take six months at most. The Female Changeling, suffering the degenerative effects of the morphogenic virus, sought additional allies to swell the Dominion's numbers and bring a quicker end to the conflict. After the initial contact, the Breen very eagerly agreed to join the war on the side of the Dominion.

Within days, the Breen launched a massive offensive against the Federation territories. Most damaging in terms of destruction and morale was a bold attack against Starfleet Headquarters on Earth — the first time open combat had taken place on Earth in over 200 years. A short time later, the Breen launched a combined offensive with the Jem'Hadar and Cardassian forces on the Chin'toka System, the only allied foothold in Dominion territory.

The Battle
In their initial assault on the allied positions at Chin'toka, the Dominion forces broke through the lines in two places. As the Jem'Hadar, Cardassian, and Breen ships consolidated their position, Starfleet and its allies rallied their starships for a counterattack to drive the enemy fleet from the system, under the command of General Martok of the Klingon Defense Forces.

Three hundred and twelve allied ships advanced on the combined Dominion fleet, and immediately opened fire in a massive volley as they entered weapons range. The Breen warships took heavy damage, and several were destroyed, but the rest launched a barrage of their Energy dampening weapon. Nearly every allied ship was engulfed in a massive energy-draining field, drifting on emergency power only.

Adrift and powerless, their deflector shields inactive, the allied fleet became easy targets for destruction by conventional weaponry. Ship after ship exploded under plasma torpedo attack, many with all hands aboard. The Defiant was among the three hunded and eleven ships destroyed. Strangely, as the few remaining ships managed to launch escape pods, the Female Changeling, overseeing the battle, ordered that the survivors be allowed to flee. She pointed out that the survivors would report back the story of the complete and utter defeat and spread fear among the rest of the allied fleets.

The allied escape pods were picked up by emergency rescue ships dispatched from the small reserve force that had held back at the edge of the system, and the survivors quickly retreated to Federation-held space.

Aftermath
The impact of the Second Battle of Chin'toka cannot be overstated. It was a massive reversal for the allies, effectively ending all offensives against the Dominion for the next month, while engineers scrambled to develop a countermeasure. Although Klingon ships quickly developed a defense, thanks to a chance modification made to the IKS Ki'tang, a Klingon Bird-of-Prey, the Federation and Romulan fleets were left vulnerable — and the Klingons were left to fight the war on their own, outnumbered twenty to one. (DS9 "When It Rains...")

It was extremely fortunate, therefore, that the Cardassian Rebellion, led by Legate Corat Damar, launched its first attack on the Dominion's Vorta cloning center on Rondac III at about the same time. A majority of the energies the Dominion would have devoted towards an all-out invasion of the Federation, Klingon, and Romulan space instead had to be focused on quashing the uprising. This bought the allies precious weeks to develop an effective countermeasure and gave them a chance to organize their forces for a single, coordinated strike against the center of the Dominion in the Battle of Cardassia two months later. (DS9 "Tacking Into the Wind", "What You Leave Behind)