Thank you for this great summary, Red Queen!

Originally Posted by The Red Queen
Conclusion: I still don't know what the hell is going on or where to go!!!

I have come to the same conclusion 😄

But there's definitely magic involved.
And aside from the butcher, every murder took place very close to the river - but maybe this is just a coincidence.

I noticed something when we were using our speak with dead token.
Our fourth question was about the dagger, and then Grom interrupts, so we never got to ask our fifth question:

Quote
“Does this dagger belong to you?”
“Never seen it in my life.”

“Done now?” the gravedigger asks.
“Yes,” the dragonborn corpse replies before going still.

At first, I thought that this was meant as a joke - but maybe Grom was afraid that the dead Dragonborn might tell us something. He was killed at the Riverveins Entrance - it would have been interesting to ask him if he saw anything suspicious in these tunnels. Maybe something associated with rituals?

I'm not sure where to go next. Riverveins Entrance would be the place I really would like to visit.