During the Vaklin insurgency on the planet Vaklin, forces ambushed a patrol being carried out by the Galactic Empire. The ambush took place in the Howling Ruins, where the insurgent forces, led by the Jedi Master Cho'na Bene, reigned down fire on the Imperials, led by Sith Lord Darth Vader as they passed through. Both sides sustained heavy casualties in the following clash, although both commanders survived to fight again. After Bene revealed himself to Vader and the fell back into nearby caverns, the surviving Imperials retreated too instead of following him.
In the year 19 BBY, shortly after the end of the Clone Wars, an against the Galactic Empire arose on the planet Vaklin. The Vaklin insurgency was instigated by three members of the Jedi Order, which had been betrayed and almost entirely destroyed by the Empire as a part of Order 66. As part of the Great Jedi Purge, the Sith Lord Darth Vader himself traveled to Valkin to fight the insurgents and soon killed one of the Jedi and imprisoned another. After the capture of the second Jedi, the insurgents harassed the Imperials for 12 days, led by the final Jedi, Cho'na Bene. On the twelfth day, at approximatley 0700 hours local time, Vader led a patrol out of the Imperial command center in the city of Vaklin Zenith, with the intention of killing or arresting Bene. The patrol included two enforcer squads of 501st Legion clone troopers, a TX-130 Fighter Tank and at least one 74-Z speeder bike, and was led, beside Vader, by a Clone trooper commander. The group entered the Howling Ruins at approximately 0930 hours local time, at which point some of the clone troopers, including CT-3632, were preforming a perimeter sweep ahead of the group. Those preforming the sweep found no activity in the area, and 3632 reported this back to CT-3636, who ordered him to change the perimeter distance and continue looking. Despite this report, forces of the Vaklin insurgency including Bene, were in fact hidden through out the ruins, laying in wait for the Imperials.
At approximately 0930 hours local time, just as the Imperial patrol entered the Howling Ruins, the insurgents opened fire on them from above. Shooting from within the ruins, the insurgents killed several clones including CT-3636, although Vader defended others using his Lightsaber. Bene, who was hidden nearby in the ruins, waited until Vader was pinned down by an explosion and then sprung forth in to action, killing two troopers aiming to help the Sith. The insurgents then maintained fire on Vader, keeping his attention, whilst the Jedi destroyed the Imperial's speeder bike and hover tank. The tank's destruction acted as a signal to the insurgents in the ruins to retreat, throwing pyro grenades as they did to provide cover. Vader killed several of the insurgents as they attempted to escape by preventing one grenade from being thrown before it exploded. Bene then confronted Vader and complimented him before offering him peace, after which he immediately retreated into a nearby set of caverns, hoping to draw Vader and his men in after him.
As Bene withdrew the clone commander informed Vader that twelve troopers had been killed in total, but that the survivors could still give pursuit of the Jedi. The Sith saw Bene's intention though, and at approximatley 0100 hours local time, ordered a retreat, knowing that pursuing the Jedi further from the city into the hazardous caverns would be deadly for the Imperials to attempt. The Imperials fell back as ordered back to the command center, where they were later attacked by the insurgents, in the hope of freeing the Jedi prisoner kept there. The details of the ambush were later recorded by Major Oniye Namada of the Imperial Security Bureau in a report titled I-1807-VAK.
The ambush first appeared in 2012 in Purge – The Tyrant's Fist 1, a comic book in the Star Wars: Purge series. The comic was written by Alexander Freed and pencilled by Marco Castiello and Andrea Chella.