Firestorm was the expansion pack to Tiberian Sun, introducing several new missions for each faction which followed on the conclusion of the main game\'s GDI campaign. Firestorm featured several new units and structures for both factions, and told a story where GDI and Nod were shown as being compelled to reluctantly join forces in order to overcome Nod\'s renegade artificial intelligence, CABAL. Prior to the release of Command & Conquer 3: Tiberium Wars in 2007, Firestorm\'s storyline was unique in the Command & Conquer series as it was the first to feature ending sequences for the GDI and Nod factions which took place simultaneously, and both of which were considered as official canon storyline. By contrast, only the actions and events which occurred during the GDI campaigns were considered canon story throughout all other Command & Conquer games, with the events portrayed in the Brotherhood of Nod campaigns having traditionally been treated as alternate \"what if\" realities.