So the blackwood company have a bad rep and are pretty much destroyed in cyrodil, does this mean that they'll go back to black marsh or will they go to a different province? Please post opinions

When I played "Oblivion", I had the impression they're all dead now. Do NPCs in the game say that there were survivors after the player character cleans house? I'm not sure.

They were new and only had the one guild-hall from what I was impressed upon.

Yeah, I think they are all dead now. Even if they aren't, there'd only be a few low ranked fighters left.

The Blackwood Company is now just a group of piss poor marauders and adventurers called the Blackwood 6-and-a-Half. When the Hist was destroyed, all notions of a Company were disbanded and whoever wasn't in the way of that insane little man who stormed their building, murdering and breaking things as he went, decided to get together and go back to what they were before they came back from Argonia: a group of piss poor marauders and adventurers.

well seeing as the lore says that they are mercinaries hired to settle uprisings in blackmarsh i would imagine that there are still alot of them who did not defect and are still following the original contract. Now if some future game where to explore blackmarsh you might find that the blackwood members are still operating in the area.

They were mercs. Any survivors would logically find employment elsewhere. If not with legitimate organizations like the Fighters Guild, then as Bandits or Marauders.