Around one thousand and seventy days after the Battle of Geonosis, Delta Squad was sent to the Wookiee homeworld of Kashyyyk in the Mytaranor sector. Following a Separatist-backed invasion by Trandoshan slavers, the Wookiee chieftain Tarfful had been taken prisoner. Tarfful had spent years combating Trandoshan slaving parties, and without him the Wookiees turned to the Republic for assistance. In response, Delta Squad was deployed to Kashyyyk in order to extract Tarfful from captivity, in a mission that would see Delta under the oversight of Advisor CC-01/425 yet again.
Delta Squad covertly inserted into Kashyyyk via LAAT/i gunship, rappelling down to the planet's surface from the troop bay. Once on the ground, the squad moved through the planet's dense jungle until coming upon the camp of the Trandoshan slavers. Battling their way inside, the squad was ambushed in a narrow corridor by Trandoshan mercenaries on the overhead catwalks, forcing them to make an escape through a maintenance shaft toward a landing zone. After securing the landing zone, the commandos caught a glimpse of a Belbullab-22 starfighter, matching its profile to General Grievous' ship, Soulless One. Continuing through the slaver's base, Delta freed a number of imprisoned Wookiees on their way to locate Tarfful before Delta's advisor tasked the squad with another objective: confirming Grievous' presence on Kashyyyk. Climbing a tower close to the General's landing pad, Delta managed a visual confirmation on the General himself, before nearly being attacked by one of Grievous' IG-100 MagnaGuards. Rushing down the tower, Delta Squad found Tarfful being escorted to Grievous' fighter by two MagnaGuards; although Tarfful was able to successfully destroy the droids on his own, Grievous fled the planet in his starfighter, leaving behind another pair of MagnaGuards. Though Grievous had initially wanted the Wookiee chieftain alive for questioning, once denied of that opportunity, the commander of the Separatist Droid Army instead ordered Tarfful dead so as to deny the Republic the valuable intelligence Tarfful possessed. Delta Squad engaged the deadly droids in an effort to protect Tarfful, although the Wookiee warrior refused to back down from his attackers. Together, the commandos and their Wookiee ally defeated the droids, and Tarfful was taken to Coruscant in order to enlist further Republic assistance.
With Tarfful free of his captors, Delta Squad assaulted another Trandoshan encampment in the forests of Kashyyyk. There, they found that the camp was not simply another Trandoshan slavers camp, but a Separatist supply base and a staging ground for a full-scale attack on Kashyyyk. With this knowledge in mind, Advisor CC-01/425 ordered the squad to infiltrate the encampment and do as much damage to the Separatists operations as possible. While assaulting the base, Delta encountered an armed minefield which they managed to deactivate, only to reactivate the mines with the arrival of a number of droidekas; using the Separatists own mines, Delta destroyed the attacking droidekas and continued on to a nearby landing pad. Fighting off waves of Trandoshan mercenaries bolstered by the arrival of a Trandoshan dropship filled with supplies and fresh troops, Delta Squad destroyed the landing platform before receiving orders to shut down the base. The squad encountered an advanced spider droid—which they were able to destroy by releasing a cargo crane's payload over top of the droid—before being joined by a LAAT/i gunship which finished off the droid presence and airlifted Delta Squad out of the Trandoshan base.
By this point in time—1,070 days after the Battle of Geonosis—Jedi General Etain Tur-Mukan had been sent to join Delta Squad on Kashyyyk by Arligan Zey; though Zey did not doubt Delta's ability to complete the mission on their own, he felt that they would benefit from Tur-Mukan's presence onworld. Upon destroying the Separatist–Trandoshan staging base, Tur-Mukan relayed the significance of the Kachirho bridge to the commandos of Delta Squad—were the bridge to be destroyed, the Separatist supply lines would be cut off, while the Wookiees would be able to construct smaller bridges to circumvent the loss, an option the Confederacy's battle droids didn't have.
Moving through an occupied market concourse, Delta fought their way through numerous Trandoshan grenadiers and heavily armed mercenaries aided by a defense force of Wookiees defending their homes, tearing Trandoshans limb from limb. After battling another advanced spider droid and countless battle droids atop the Kachirho Bridge, Delta Squad placed a detonation pack at the center of the bridge where it was weakest. However, when Boss attempted to detonate the charge, the explosives suffered a misfire. Undeterred, Scorch borrowed a rocket launcher from a female Wookiee, and used it to destroy the bridge. Thirteen days later, Delta would continue operations on Kashyyyk, even as Coruscant came under attack by General Grievous. While preparing to ambush a Separatist droid patrol, Scorch and Sev listened in to the comlink traffic from Coruscant, learning that only commandos in the Inner Rim had received the Code Five signal to return to Coruscant immediately. When General Tur-Mukan expressed her concern for her loved ones residing on the Republic's besieged capital, Delta Squad took it upon themselves to comfort her, and when she revealed that she had a son, they promised to keep her secret. Though the battle droid patrol would fall victim to Wookiee-make pitfalls, Delta and Tur-Mukan ambushed a small group of Trandoshans scouting through the Wroshyr trees, disposing of their dead bodies via a carnivorous plant.
Five days later, with the crisis on Coruscant over, Delta Squad was joined on Kashyyyk by the clone forces of Jedi General Quinlan Vos, arriving from Boz Pity. In addition, General Yoda was inbound with the 41st Elite Legion and Wookiee Chieftain Tarfful, set to land within thirty standard minutes. However, a Recusant-class light destroyer had taken up position to engage Yoda's cruiser and halt the debarking of additional ground troops. With a bit of good-natured coaxing from General Tur-Mukan, Delta Squad infiltrated a Separatist turbolaser battery complex with the intent to commandeer the contained firepower to take out the Recusant-class destroyer. With Clone Commander Gree considering alternative landing sites—each too far removed from the main offensive to be effective—Delta Squad captured one Wookiee dual missile turret for each commando, and opened fire on the Commerce Guild destroyer, joined in the attack by a wing of General Vos' LAAT/i gunships. After sustaining heavy damage, the Recusant destroyer began to fall, but while the majority of Delta Squad planned for a hasty exit, Sev radioed in with a report of coming under attack from multiple hostiles. When Boss ordered the squad to go back for Sev, Vos' Forward Air Controller instead ordered Delta to leave, stating that the order had come directly from General Yoda himself. Though Scorch argued to the point of tears, Boss forced him to comply and moved the remaining three members of Delta Squad onto the gunship that had arrived to extract them, but not without first making a guilty apology to Sev.
Onboard the gunship, Advisor CC-01/425 confronted Boss via hologram and ordered him to get his squad under control. The advisor then patched through a transmission from General Yoda, who stated that Delta Squad's efforts had enabled the Republic to establish forward command in Kachirho, and that the Republic would continue to rely on their skills in the coming battle. Delta Squad was then retasked with a new set of objectives for Kashyyyk.