Ashen Scar

In an alternate timeline where the Vulcans had remained a violent and emotional species, the Ashen Scar was a swirling rift to another dimension created by the use of subspace weapons. The anomaly was straddled the border between the Interstellar Union and the Klingon Empire. The Ashen Scar was located in the vicinity of Mu Arae. 

History and specifications
The Ashen Scar was created during the early expansion of the Klingon Empire by the deployment subspace weapons. The amount of gravitational and photonic energy emitted by the anomaly blinded sensors and had resulted in the loss of a dozen starships by the late 23rd century.

In 2293, the Interstellar Guard starship IUES became the first ship to successfully pass the Ashen Scar in close proximity. The Kumari was returning from a reconnaissance mission in Klingon space when it was forced to take the shortcut back to IU space.

The presence of a trio of battlecruisers deeper in the Scar impinged on the anomaly's subspace field, alerting Commander Hikaru Sulu by causing tremors. The Kumari fired photon torpedos into the Scar, forcing the Klingons out and slipping back into IU space undetected. The D8-class battlecruisers retreated with the wreckage of sensor drones in tow.