This battle took place roughly two months after the Declaration of War by the Sith Council. After taking so many of the Nymean Ascendancy's outer planets, the Galactic Alliance decided to attack the capital planet of Areltsi hoping to end resistance in the sector.
Early on in the battle, Darth Perfidious, who was commanding a small group of frigates back from an escort run to Ni'novia, was killed. The Nymean fleet that was there was not prepared for the fight and was quickly driven off. The planetary shields were breached and the Galactic Alliance landed over 300,000 troops.
The defenders, who numbered less than 100,000 trained troops and 200,000 militia, were quickly driven away from Ahid City and other major cities. Only the arrival of Trivas and Xiann with 70,000 reinforcements and a small fleet including the Incalculable II were the defenders prevented from being overwhelmed. Even then, the reinforcements were not enough.
Trivas was about to order a retreat when Lord Xaos arrived with an additional 75,000 troops and a large fleet from the Obsidian Union did the Sith manage to turn the tide and win. For his help, Trivas granted aid to Xaos in overthrowing Nefarious and restoring prosperity to the Obsidian Union.