CABAL

Rumor has it CABAL was originally created by Kane to be the AI for both Kane and Nod near the end of the First Tiberium War. (in Tiberian Dawn) CABAL was first used near the start of the Second Tiberium War assisting Slavik on his campaign to kick Hassan out of power and restore the glory of the Brotherhood of Nod and afterwards, he was used to help Nod fight against GDI. Eventually (in the Firestorm expansion pack) Nod would bring CABAL back online after GDI decommissioned him and CABAL would have the Brotherhood of Nod do such inethical tasks and missions (such as unleashing Tiberium creatures on Civilian populations, assasinating Tratos and an all out assault on Shiner populations.) then CABAL turned on Nod, using Cyborgs to kill all the Nod officials in the inner circle except for Slavik, just after CABAL's betrayal, the GDI took control of CABAL (or thought they did) but in reality, CABAL was only using GDI and Dr. Budreau to locate peices of the Tacitus. After CABAL used GDI, he starts going on a all out assault on the GDI, Nod and Civilians and Shiners (Tiberium mutated humans for those who don't know) populations, capturing organic components for his cyborg army. In the last GDI and Nod firestorm missions, CABAL has a huge powerful bad-ass mech called the "Core Defender" protecting his main core. Once you defeat him on the Nod missions, you will see the ending scene that reveals CABAL's true identity...I'm not telling, you're just going to have to find out yourselves.