The Sword Impulse Gundam Spec II is an upgraded combat variant of the Impulse Gundam Spec II, customized for high-mobility melee engagements. Equipped with the Sword Silhouette pack, it features an enhanced Variable Phase Shift armor, giving it a unique color scheme distinct from the original Sword Impulse Gundam. Despite this aesthetic change, its performance remains in line with its predecessor.

Originally, the Impulse Gundam Spec II was one of three mobile suits secretly upgraded by Erica Simmons at the request of Cagalli Yula Athha and stored in a hidden hangar on Orb Union’s Akatsuki Island. In C.E. 75, it was deployed aboard the LHM-BB03S Millennium, a vessel operated by the world peace organization Compass, to replace lost mobile suits. The Sword Impulse Gundam Spec II later saw intense combat during the battle against the Kingdom of Foundation, where Lunamaria Hawke piloted it against multiple adversaries, including the NOG-M4F Rud-ro.As and ZGMF-2027/A GYAN Strom.

During a fierce duel with Agnes Giebenrath, Lunamaria’s Excalibur laser swords were destroyed, forcing her to rely on Flash Edge beam boomerangs to counterattack. As her mobile suit's battery depleted and the Sword Silhouette’s weapons were exhausted, she transitioned to the Force Silhouette, receiving a Deuterion Beam recharge from the Destiny Gundam Spec II to continue the fight.