Wait wait so are shadowscales gone? Just like that with 2 games?
Yep.
I don't understand how the Dark Brotherhood lost footing in Black Marsh though. If the Shadowscales are trained by the Dark Brotherhood and work in service of the King of Black Marsh, you'd think that the Brotherhood would have safe haven there. Sorta like the Morag Tong, another group of assassins that got completely wiped out for Skyrim's whole "everything in the world svcks" storylines.
It also doesn't make sense in that...Shadowscales are independent of the Dark Brotherhood. Dark Brotherhood =/= Shadowscale, so why should the troubles of the Dark Brotherhood fall back on the cultural concept of Shadowscales? You would think that if the Dark Brotherhood, the go-to organization for Shadowscales, was in trouble, then they'd simply find another group to send their Shadowscales to. Shadowscale is a cultural concept, and I fail to see why what's essentially a company should be able to impact a tradition; just find a different company?
The whole thing is as if the Khajiit decided they were gonna do away with the concept of the Mane because the Mages guild is no more. I'm sorry, what? The moons are still there, much like the sign of the shadow and it's month are still there. I don't see why an organization dissolving or having financial trouble should impact any of that.