I highly doubt they are gone...and with the DB back in shape...there will be more again someday. The Dark Brotherhood will never die, nor will Argonia. The Shadowscale sleep, and when they awaken all of Tamriel will know what true fear feels like.
They were never truly gone. In time, Argonia will use them again, and when this happens, the Thalmor will know regret.
True however Shadowscales aren't being trained as it currently stands, one day they will be trained again, then Argonia will have it's assassins back again, they'll better be able to defend their borders.
Amazing detail and amazing job on this i loved these guys in Oblivion but was sad to not see them in Skyrim
Well, just one is there in Skyrim, which is half of what was in OB.
Deadliest assassins in all of Tamriel!
That's quite dark!
Now that is some crazy awesomeness.