Code name: Thunderstroke designated a mission authorized by Imperial Regent Morlish Veed that centered on an ambush of a clandestine meeting set to occur between the exiled Galactic Emperor Roan Fel and individuals from the Jedi Order. Under the command of Moffs Rulf Yage and Fehlaaur'aitel'loro aboard the War Hammer, the Imperials aimed primarily to seize Fel, intending to subject him to trial and subsequent execution, thereby effectively dismantling the resistance movement of his exiled forces.
The First Sith Imperial Strikeforce, a division of the Imperial Navy comprised of members from the One Sith, was designated to execute the operation, spearheading Skull Squadron from their Fury-class starfighters. The strikeforce was unsuccessful in their primary objective, as Emperor Fel managed to evade capture. Nevertheless, the Sith successfully apprehended Princess Marasiah Fel.
Upon hearing the news of Darth Krayt's passing, the remaining members of the Jedi Council decided to join the conflict alongside the newly established alliance between Fel's resistance and the surviving Galactic Alliance forces, led by Gar Stazi. Agamar, an agricultural planet situated on the periphery of Fel-controlled territory, was chosen as the meeting place.
Information regarding this rendezvous reached Imperial Regent Veed through the Sith, prompting him to devise an assault to capture Roan Fel and his daughter, with the intention of subjecting the deposed monarch to a public trial and execution. Veed believed that by eliminating Fel, his Empire-in-exile would inevitably collapse. He named the operation "Operation: Thunderstroke" and tasked Moffs Yage and Fehlaaur with overseeing it and commanding the First Sith Imperial Strikeforce, a Navy unit consisting of pilots from the One Sith. Yage, however, harbored resentment towards leading what he perceived as "monsters."
Protected by his Imperial Knights, Fel landed on Agamar, awaiting the arrival of the Jedi delegation, which included Jedi Masters K'Kruhk, also a member of the Jedi Council, Rasi Tuum, and Hira, as well as Jedi Knight Shado Vao. Both groups adopted the attire of Agamar's farmers to avoid detection, although the Imperials were already en route. The Jedi agreed to collaborate with Emperor Fel and Admiral Gar Stazi, coordinating their attack with them. In return, both Bastion and Stazi's forces would provide sanctuary to the Jedi.
Moff Nyna Calixte journeyed to Agamar to alert the allies, landing her starfighter at a remote farm to avoid alarming either faction. After compensating a native farmer to conceal her vessel, Calixte proceeded to the meeting aboard a borrowed Agamarian beast, disguised in the farmer's cloak and hat.
The Imperial Knights detected Calixte's approach and opened fire upon her, perceiving her as a threat. Emperor Fel recognized her and ordered the shooting to cease. Surrounded by lightsabers, Calixte warned both parties that the Sith were aware of the meeting and would arrive imminently to hunt down Emperor Fel.
At that precise moment, the Sith forces, led by Yage's Pellaeon-class Star Destroyer, the War Hammer, emerged from hyperspace and engaged Fel's own Star Destroyer, the Dauntless.
The War Hammer launched its squadrons of Sith-Imperial starfighters and Sith Furies to assault the Dauntless and the delegations on the planet's surface. Onboard the Dauntless, Admiral Tohri Challon instructed her crew and pilots to engage the Sith Imperial forces, aiming to create a window of opportunity for Emperor Fel to escape.
As the space battle unfolded, numerous Fel loyalist pilots ejected from their damaged Predator starfighters in an attempt to survive. However, Darth Rauder, the Sith Lady commanding the strikeforce pilots, ordered Captain Gunn Yage to eliminate them as well. When Yage refused to comply with Lady Rauder's orders, the Sith threatened to kill her using the Force if she did not obey. Rauder utilized her telekinetic abilities to apply pressure within Yage's head, causing her to bleed from her nose and eyes. However, to save Yage's life, Lieutenant Tev Rimon fired at the pilot, provoking Lady Rauder's anger, who demanded that Yage personally shoot at the enemy pilots and threatened to kill Rimon if he defied her orders again.
As Emperor Fel prepared to flee, the delegations were attacked by a group of several Sith, including a Dashade, a Zabrak, and a Devaronian. The Jedi and Imperial Knights fought together to protect Emperor Fel, enabling him to reach his shuttle, the Defender One, and eliminating some of the attacking Sith in the process. However, Master Hira was killed when a Nautolan Sith struck her with Force lightning.
Fel reached his shuttle along with Masters Antares Draco and Treis Sinde, while Princess Marasiah Fel, Imperial Knight Azlyn Rae, and Master Rasi Tuum held off the enemy. Before the three could board the shuttle, however, several enemy fighters approached. Although Master Draco wished to rescue the Princess, Master Sinde reminded him that the Emperor's safety was his priority and that they needed to leave the planet. As Fel, Rae, and Rasi Tuum were overwhelmed by enemy fire, Draco ordered the shuttle's pilot to evacuate.
In space, the War Hammer had inflicted significant damage to the Dauntless, whose shields had already failed. Nevertheless, Admiral Tohri Challon instructed her crew to continue fighting until the Emperor's shuttle had jumped to hyperspace. The shuttle successfully escaped, but the Dauntless was destroyed. Admiral Challon, her second in command, Captain Basile, and the entire crew of the Star Destroyer perished.
Although the operation's primary objective was not achieved, the battle did not constitute a defeat for the Sith Empire. The War Hammer successfully destroyed the Dauntless, depriving Fel's fleet of a valuable starship and a loyal Admiral, while the Sith dispatched to the planet succeeded in achieving the mission's secondary objective: the capture of Princess Marasiah Fel. Alongside Princess Sia, Azlyn Rae and her former Master, Rasi Tuum, were also captured.
Emperor Fel managed to escape to hyperspace with Antares Draco and Treis Sinde, thanks to the efforts of his Knights and, in particular, the deaths of Admiral Challon and her crew. Once safely in hyperspace, Fel acknowledged the noble sacrifice of his soldiers, which he had witnessed as the Defender One flew above the War Hammer. The Force also enabled Fel to sense that his daughter had survived the attack and was in the custody of the Sith. He ordered Master Draco to rescue her, a task Draco vowed to accomplish.
It was later revealed that Hogrum Chalk, the Emperor's brother-in-law and the Imperial Knights' master armorer, was the one who betrayed Fel to the Sith.