During the New Republic era, the First Order initiated an assault upon the [iron](/article/iron] planet of Demir, located within the Unknown Regions.

On the metallic world of Demir, First Order stormtroopers, accompanied by an AT-ST and TIE/sf space superiority fighters, clashed with Demirian warriors and their spacecraft. Captain Phasma spearheaded the stormtrooper advance, eliminating several Demirians. Subsequently, Phasma informed the stormtroopers that the AT-ST would pave the way to the Demirian stronghold. Following this, she commanded the stormtroopers to maintain readiness and act decisively. Phasma then addressed the troops, likening them to extensions of her will. She elaborated that any failure in their aim or resolve would render them unworthy of her command and service to the First Order.
A stormtrooper alerted Phasma to an approaching Demirian vessel, prompting Phasma to order the stormtroopers to seek cover as the ship prepared to fire. The vessel unleashed a powerful blast, obliterating the AT-ST and scattering the stormtroopers. KM-8713 regained consciousness and removed their helmet. Noticing DB-7197, a fellow trooper from their basic training, wounded on the ground, they assisted him in standing. As the injured troopers began to rise, KM-8713 reassured DB-7197 that they would remain together. However, Phasma instructed KM-8713 to abandon DB-7197, despite KM-8713's insistence that he would not impede their progress. Phasma reiterated her order to leave him, but before she could finish, KM-8713 warned her of an impending Demirian ambush. KM-8713 neutralized the Demirian using their F-11D blaster rifle, but the falling Demirian released a thermal detonator. Phasma seized DB-7197 and threw him onto the thermal detonator, as KM-8713 cried out in horror. The trooper's body absorbed the explosion, allowing Phasma and KM-8713 to survive. Phasma then informed KM-8713 of their withdrawal to regroup, adding that KM-8713 would report to her command shuttle to discuss the events of the battle.
Aboard Phasma's shuttle, she promoted KM-8713 to lieutenant, recognizing a shared quality between them. She informed the newly appointed lieutenant that the Demirian base held strategic importance to the First Order, necessitating its capture rather than destruction. Outside the Demirian stronghold at dawn, with KM-8713 by her side, Phasma declared to her stormtroopers that the field would be their ground of victory and that they would seize control of the stronghold, regardless of the opposition. She then delegated command to KM-8713, who ordered the troops to advance. As the Demirian stronghold's doors opened, KM-8713 instructed the troopers to open fire. The Demirians deployed their vehicles and launched large energy bolts that devastated the stormtroopers. A stormtrooper reported to KM-8713 about the numerous casualties and wounded. Another stormtrooper expressed doubt about their ability to penetrate the Demirian vehicles' armor. KM-8713 urged the stormtroopers to maintain their fire. KM-8713 continued to fire, chanting about the glory of the First Order. The lieutenant then noticed Phasma retreating from the battlefield. KM-8713 pursued her and inquired if there was a problem. Phasma assured them that everything was according to plan, stating that they had successfully drawn out the enemy, and then ordered the lieutenant to return to the fighting, but they insisted that the stormtroopers needed her assistance. Phasma repeated her command for KM-8713 to rejoin the battle. KM-8713 then heard the sound of TIE fighters and was surprised to see them overhead.
The TIE fighters unleashed destruction upon the battlefield, eliminating all in the area, including the stormtroopers, leaving KM-8713 in shock, who then pleaded with Phasma to recall the TIEs. KM-8713 then recalled Phasma's words about calculated sacrifices, realizing that Phasma had used the other stormtroopers to expose the Demirian stronghold and lure the enemy into the open. Phasma confirmed this, stating that KM-8713 had fought bravely and survived. KM-8713 then declared that the other troopers would learn of Phasma's betrayal, believing it to be their opportunity to advance within the First Order. KM-8713 then confronted Phasma, denouncing her as a coward and firing upon her. Phasma's blaster was dislodged from her grasp, but she remained standing. Phasma cautioned KM-8713, emphasizing the value of her armor over the lieutenant's life, and engaged in a struggle with KM-8713, asserting that she was not a coward. Phasma then seized KM-8713's blaster and proclaimed that she leads as all great leaders do-behind a shield of patriotic idiots. Phasma then shot KM-8713 in the chest with their own blaster. As KM-8713 lay dying, they implored Phasma not to abandon them to their fate. As Phasma departed, she stated that she could not see her goal if she was looking over her shoulder. As TIE fighters flew ahead, Phasma left the battlefield of fallen stormtroopers and Demirian vehicles behind, noting KM-8713 was just another nameless, fallen gun.
The assault on Demir was depicted in the one-shot comic Age of Resistance - Captain Phasma 1, released by Marvel Comics on July 10, 2019. The comic's narrative was crafted by Tom Taylor, with illustrations by Leonard Kirk.