Been adventuring about 10 hours and still haven't come across any. I've encountered the Morag Tong. Anyone found Dark Brotherhood?

Are they supposed to be there?

Almost sure there are no dark brotherhood.

Indeed I too am almost sure there will be no Dark Brotherhood on Solstheim.

The Dark Brotherhood does not exist on Solstheim for obvious reasons - it's Dunmer territory, which means Morag Tong territory, unless I'm deeply mistaken.

The two organizations have a wee bit of a grudge match going, so just like rival gangs in real life, they're not gonna tolerate encroachment on each other's area. Plus, the Skyrim Dark Brotherhood is hardly worthy of the name.

The Dark Brotherhood goes extinct in every game for some contrived reason, of course they aren't there.