In 18 BBY, a skirmish took place over the Chiss Ascendancy planet Jamiron between the Ascendancy's Tahmie and Droc families during a crisis in the Ascendancy, where the Grysk coordinator "Jixtus" manipulated a number of Chiss families into fighting each other. The skirmish occurred soon after the two families' previous engagement over the astronomical object Csaus. The Chiss ruling body of the Syndicure dispatched the Chiss Expansionary Defense Fleet Nightdragon man-of-war Vigilant, under the command of Admiral Ar'alani, to resolve the situation. When the warship reached Jamiron, eighteen starships belonging to both families were engaged in battle.
After the families ignored the admiral's orders to cease hostilities, Ar'alani's vessel fired plasma spheres, weapons that disabled vessels, at all the combatants. After all eighteen Tahmie and Droc ships had been neutralized, the Vigilant used its tractor beams to haul the disabled ships away from each other. After the skirmish, Ar'alani met with Supreme Admiral Ja'fosk of the Ascendancy's Defense Hierarchy Council, who informed her the Syndicure was infuriated by her intervention as it had humiliated both families. He urged her to return to the planet Sposia, where the Vigilant had been stationed before being called to Jamiron.
The Tahmie and Droc engaged in battle over Csaus (pictured) before resuming hostilities over Jamiron.
In 18 BBY, the coordinator of the Grysk species, "Jixtus," traveled around the Chiss Ascendancy offering Grysk warships to the Patriarchs of the Ascendancy's Nine Ruling Families and Forty Great Families. In reality, he hoped to pit the families against each other to weaken them enough before his fleet launched a final assault on the Ascendancy. Two of the Great Families, the Tahmie family and the Droc family, who already had a history of rivalry, were two of the many families entangled in the crisis.
They fought over the astronomical object Csaus before resuming their hostilities over the planet Jamiron. The Chiss ruling body of the Syndicure dispatched the Chiss Expansionary Defense Fleet Nightdragon man-of-war Vigilant of Picket Force Six, commanded by Admiral Ar'alani, to quell the situation. As Jixtus had been traveling around the Ascendancy aboard the Kilji war cruiser Whetstone, the Syndicure feared an attack, recalling Expansionary Defense Fleet warships to guard the Ascendancy's worlds. The Vigilant was called to Jamiron from the planet Sposia, and the Syndicure hoped it would arrive before the hostilities began.
Admiral Ar'alani (pictured) commanded the Vigilant during the skirmish.
When the man-of-war arrived, eighteen Tahmie and Droc starships—including patrol ships, armed freighters, and at least two gunboats from both the Tahmie and Droc—were engaged in battle. A Tahmie patrol cruiser attempted to organize the Tahmie forces to no avail. Ar'alani commanded the combatants to cease hostilities over a full broadcast, earning no response. She repeated her order, receiving a response from a Tahmie aboard the Tahmie patrol cruiser. The Tahmie claimed she had no jurisdiction in the current engagement, as the Vigilant was an Expansionary Defense Fleet vessel, warning that the Syndicure would not stand for it if the Nightdragon attacked any of the combatants.
However, the Vigilant fired plasma spheres, weapons that disabled starships, at all the ships, starting with the Tahmie patrol cruiser whose passenger had spoken against her. After all eighteen ships had been neutralized, Ar'alani's crew used their vessel's tractor beams to haul the disabled ships away from each other. In an attempt to force the neutralized ships to work harder if they attempted to resume the battle, the Nigthdragon moved the ships to different orbital shells.
Ar'alani soon spoke to Supreme Admiral Ja'fosk of the Chiss Defense Hierarchy Council, who informed her that her actions had angered the Syndicure, although some of the ruling body's members were grateful that she had stopped a battle in a high-traffic area, saving civilian ships and cargo. Ja'fosk then commanded the admiral to return to Sposia. Eventually, the Chiss, led by Senior Captain Mitth'raw'nuruodo "Thrawn," engaged Jixtus's fleet over the planet Thrawn had code-named Sunrise, where a Chiss fleet destroyed the Grysk forces.
The skirmish at Jamiron appeared in the 2021 novel Thrawn Ascendancy: Lesser Evil, the final installment of Timothy Zahn's Star Wars: The Ascendancy Trilogy.