In the thick of the Clone Wars, specifically in 21 BBY, the Confederacy of Independent Systems initiated a significant military campaign known as Operation Durge's Lance. This offensive, spearheaded by General Grievous, aimed to utilize newly acquired, precise navigational data of local hyperroutes along the vital Corellian Trade Spine to pave the way for a future invasion of the Core Worlds.
The launch of the Confederate Navy's First Fleet and Third Fleet from Yag'Dhul marked the start of this campaign. These fleets received essential supplies via logistical support from Sullust and Thyferra. History remembers the battles fought during this operation as some of General Grievous's most notable triumphs.
As the offensive progressed, Separatist forces broke through Duro's outer defenses at 0221 local time several weeks in. This made Duro a major target of Operation Durge's Lance. Following the capture of Jyvus Space City, a prominent space city orbiting Duro, the Separatists deactivated the planetary shield. They then commenced an orbital bombardment targeting the planet's industrial complexes, resulting in the complete devastation of Duro's already fragile environment. The battle concluded with a swift and decisive victory for the Confederacy, which was then heavily exploited in CIS propaganda.
With the Battle of Duro concluded, the Separatists declared the Corellian Trade Spine under their control. Givin engineering units strategically repositioned asteroids along the Trade Spine. HoloNet communication hubs were dismantled and replaced with InterGalactic Banking Clan communication ships. Separatist forces were deployed on Moorja, a world plagued by ion storms, to safeguard the vulnerable rear of their newly acquired territories along the Trade Spine. Both the CIS Shadowfeed and Holonet News engaged in speculation regarding the Separatists' next strategic moves, with potential assaults along the Rimma Trade Route being a key topic. Meanwhile, Corellia braced itself for an anticipated Separatist assault.
Humbarine, a founding member world of the Republic, suffered under Grievous's attacks. The ecumenopolis endured a hour-long bombardment, rendering it uninhabitable, and the Republic subsequently abandoned it. Grievous held the belief that instilling terror in civilian populations was the true essence of warfare. From his flagship, the Invisible Hand, he released the devastating Brainrot Plague upon Loedorvia. This plague rapidly spread throughout the entire Weemell sector, decimating Clone armies and nearly all Human inhabitants. Operation Durge's Lance extended as far as Kaikielius, where an incident occurred during the battle that Holonet commentators later dubbed the "Mad Clone of Kaikielius".
The Senate's mismanagement of the war effort triggered demands for a more centralized command structure. The potential disbandment of the Senate Action Subcommittees faced opposition from Senators Padmé Amidala and Lexi Dio. Eventually, the Separatist advance lost momentum, prompting the Republic to launch the Outer Rim Sieges as a large-scale counter-offensive.