The Firestorm campaigns left Nod exhausted and fragmented as the smaller outposts were hit by CABAL who had relatively accurate Intel on Nod activities. He knew where all of Nod's bases were, what their function was and how to best attack them. CABAL tapped into Nod's communication network before his main core was destroyed and released a devastating virus that later disrupted any of Nod's Tacitus-related devices, causing what was left of the brotherhood's technology of peace to malfunction. Banshees literally fell from the skies and stealth tanks or generators would either instantly uncloak and shutdown or have their generators overload, it was a disaster beyond anything the brotherhood could have ever imagined. The damage could sometimes be undone by retrieving old data matrices, but the blows dealt by the AI were devastating to even the integrity of the splintered factions themselves, and they were largely forced to improvise and downgrade. The stalemate between GDI and Nod was quickly broken by GDI a few months after the crippling of Cabal. The Black Hand was destroyed and Nod was cast down for the third time in history.
Despite Nod no longer being unified and spiralling down into chaos, a few of the larger splinter cells have stood their ground in southern Europe and central Africa, where they absorbed some of the local militia in their efforts to stay alive. However, GDI is too occupied with tiberium to worry about Nod now that they're no longer an immediate threat, but they are aware of Nod's ability to remain in hibernation for several decades and then suddenly resurface with renewed strength, so GDI military activity is at peak level and they keep a close eye on any suspicious activity.
No Slavik? That's too bad! A great backstory though!
Hmmm, Slavik isn't mentioned... maybe he could be cloned or somehow preserved? :->
It's likely slavik and the remainder of black hand survivors have gone underground, awaiting the resurrection of kane. Possibly the Black Hand will make a appearance later on in the campaign. Either as friends (For staying true to the nod cause) or as enemies.
A nice intro! Maybe more background stories would be needed - especially what these larger spliter cells did next. :-)
You'll have to play the campaign, the splinter cells will be explored more thoroughly there.
I have already created a couple of Nod basic tanks to give a little bit of variety between the splinters, and make which splinters you ally yourself with a little more interesting.