New units for both sides have been added, including: The game's executable has been modified to run both Tiberian Sun and Firestorm by choosing either game upon running. It was implied that what was left with CABAL merged with the consciousness of Kane.ДЇirestorm adds new campaigns for both sides, both of which are canon, and which occur simultaneously. However, unbeknownst to both GDI and Nod, Kane remained alive, albeit in stasis, inside one of the hidden bunkers storing CABAL's organic components. Meanwhile, the reunited Nod celebrated their victory with Slavik as their undisputed leader. GDI captured the complete Tacitus from CABAL, which gave them a vast wealth of knowledge. However, it was defeated in the end, and its core was destroyed. During the joint assault on its heavily defended core, CABAL unleashed the Core Defender, a nigh-invulnerable giant walker. Finally, the two factions pinpointed the location of CABAL's true core after sharing their intelligence. GDI forces attacked CABAL's cyborg production plant while Nod destroyed one of its major Tiberium harvesting operations. Cortez and Slavik were left with forced to declare a temporary alliance to take down CABAL.

However, the core was yet another decoy, and CABAL devastated Nod's strike team with missile strikes. While GDI focused on evacuating its civilian population, Nod launched a desperate attack on CABAL's core.

GDI destroyed the CABAL core in the Daedalus lab, but it turned out to be merely a remote controlled terminal.Д¬ABAL's cyborgs captured civilians and soldiers alike, and converted them into more cyborgs. CABAL declared its intention to exterminate all of humanity as its cyborgs slaughtered both GDI's Daedalus Team scientists and Nod's Inner Circle generals. To speed up the Tacitus research, and with it the process of Earth's recovery, GDI decides to capture CABAL.ДЄfter capturing what they believed to be CABAL's core, GDI forces recovered a missing segment of the Tacitus based on CABAL's intelligence, only for the AI to reveal that it has been manipulating both them and Nod in order to complete the Tacitus. Gabriella Boudreau predicted that the Earth's atmosphere will be 100% toxic to humans in less than a year. Time is running short, as GDI scientist Dr. Tratos' death was a major blow to GDI, as it not only severely damaged the relationship between GDI and the mutants, but also rendered them unable to translate the Tacitus. As GDI forces scrambled to restore order in multiple sectors, Nod forces assassinated Tratos on CABAL's orders. In order to reunite the Brotherhood, Nod recovered CABAL from GDI and threw their forces into disarray by luring Tiberian creatures to attack their civilian settlements. The taskforce successfully recovered the Tacitus from the Kodiak's wreckage. In response, General Paul Cortez at Southern Cross assumed command of global GDI forces and formed the Firestorm Taskforce. However, as GDI forces were transporting the Tacitus to Tratos' compound for translation via the Kodiak, a massive ion storm caused the Kodiak to crash and cut off GDI forces worldwide from their headquarters, the space station Philadelphia. Tratos believed that the solution to Tiberium could be found in the Tacitus, the alien data matrix vital to Kane's plan. To make matters worse, the mutant antigen developed by Tratos and tested on Umagon turned out to be a failure, and the latter was driven insane by her mutation. Meanwhile, even though the Global Defense Initiative has won the war against Nod, they were losing the war against Tiberium, which continued to spread unchecked, poisoning the Earth. With the apparent death of Kane, the Brotherhood of Nod fractured as the generals of the Inner Circle each vied for power and Anton Slavik, Kane's right-hand man, struggled to maintain control.

Tiberian sun firestorm walkthrough