The Eternal Crisis

The Eternal Crisis was a series of clashes on the planet of Csilla and elsewhere in the Chiss Ascendancy between the Jedi, the Sith, and their Chiss Sympathizers.

Prelude
Years after the Great Crusade's conclusion, Natalia H'edan, the Grandmaster of the Jedi Order, and a Alliance Hero, would send delegates to the Chiss Ascendancy wishing for an alliance due to great mutual relations as of late, however, the Sith had the same idea, and were already long time friends of the Chiss. The Jedi and Sith delegates, who were respectively Jedi and Sith themselves, were brought upon the Council to determine who's offer would be taken up. A disagreement between the delegates would lead to an arguement, and an eventual duel, which the Sith won, but left survivors, who would inform the Jedi Order.

Opening Days and the Csilla Front
Natalia H'edan arrived personally on Csilla with around 100 Jedi to combat the Sith, where she was met by a large amount of Alliance supporters who had taken up arms. With her Jedi, and the armed sympathizers, she'd march on the Sith who had had the same encounter with their Supporters, who were a bit more numerous in numbers. A battle began between the two which eventually forced both to entrench, and causing the battle alone to last 7 years.

Duel of the Destructor
Darth Talgus' flagship, the Conqueror, was under major repairs and refitting, and because of this he took a smaller, less powerful cruiser to Csilla, the Destructor. This ultimately lead to his demise, as the Destructor had terrible AA support, and required a large escort to defend it, which the escort at the time were under repairs due to a recent confrontation. As he attempted to land the ship on the planet, he was boarded by 4 Jedi, including Natalia H'edan, and around 200 Chiss Sympathizers, who cleared a path to the bridge. The duel began, and ultimately culminated in Darth Talgus disposing of three Jedi, and Natalia H'edan dealing the final blow. The ship was set on a course into a nearby mountain, while the Chiss and H'edan withdrew from the ship. The sudden death of Darth Talgus lead to a small period of infighting among the Sith.

Closing Days and the Time of Two
As the war began to calm down, and battles became skirmishes, the 7 year long Battle of Csilla ended in an ultimate stalemate. Both sides had taken around about as much losses as the other, and no one had gained much ground. Soon, Darth Medicus was killed by Natalia H'edan's Padawan, Amelia Radeni in a duel, and Darth Tyrus succeeded him. 252-262 ABY soon became known as the Time of Two by the Sith. Darth Tyrus showed horrible skills as a commander, which led to the Sith being pushed out of the Csilla System entirely. However, he was not nearly as weak as a duelist, as when he fought Natalia H'edan in the bridge of his ship, formerly Darth Talgus' ship, The Conqueror. Natalia H'edan inflicted heavy wounds onto him but he soon got the upper hand, slashing her across the chest and defeating her. H'edan would be saved by a Chiss strike-team before she could be executed. His ship's crew were all killed in the duel, which forced the ship to make a crash landing on an Unknown Planet in the Unknown Regions. Stranded, Tyrus died of his injuries, and once his body was found by a Jedi, an Admiral took temporary command of the Sith Empire, forcing the Order to sign the Treaty of Csilla, which basically was just a White Peace.

Aftermath
The aftermath was not notable, as casualties had been small and both the Alliance and Sith Empire were basically unaffected.