Arriving on Coruscant aboard his TIE Advanced x1 and speeding past and Imperial checkpoint looking for any sign of the Scourge, Vader was shot down but crashed into the Imperial Palace, where he was surrounded by a grouping of stormtroopers from a Lambda-class T-4a shuttle. Vader soon wiped out every trooper who was sent against him, including members of his own death trooper guard who were ordered to turn on Vader by the Emperor. Sidious used the battle to claim to Vader that, without his blessing, he had nothing to command, further questioning if he was in control of his own hate. Soon enough, the collected spider-droids escaped Vader's TIE Advanced x1 and infected the death trooper corpses as Vader struggled with Sidious. While Vader neck snapped each trooper and lifted them into the air to prevent their escape into the Lambda shuttle, he threw the spider-droids out into Imperial City, where the Scourge used them to find and infect droids to massacre the populace.
While Sidious struck down several droids with his Force lightning, taking several civilians with them, the infected droids made it out into the city, where they quickly killed up to one hundred citizens. To protect his capital, Sidious ordered Grand Vizier Mas Amedda—who, like Sub-Administrator Sly Moore, was disturbed by Sidious's casual execution of citizens along with the Scourged droids—to wipe out and under . As laser weaponry destroyed both sectors, destroying any Scourged droids at great cost to the city, Sidious explained the source of his power: while Vader's hatred for Sidious did indeed increase his power in the dark side, Sidious himself thrived off such hate. As such, the more Vader or any of his other followers hated the Emperor, the more powerful the man became. Vader was allowed to leave Coruscant in silence aboard the Lambda, aboard which the Scourge used a surviving spider-droid to tell Vader that, by bonding with it, he would finally be powerful enough to defeat Sidious. Vader willingly allowed the Scourge to infect him but quickly separated his armor from the Scourge at large, protecting himself as he began to create a Scourge infection of his own on Mirgoshirax.