I decided to make a detour to Fort Dawnguard to let them know of Strogan's fate. While Einer tagged along, the sisters went off to seek out the next Dragonslayer. Would be a while before I rejoined them though, for at Fort Dawnguard I was informed that Njada was captured by vampires!? Vampires likely allied with the Dragonslayers methinks.
Not wasting any time Einer and I headed to Morvunskar to deal with the scum, easily annihilating the exterior guards. Someone had beaten us inside though, and was happily killing all the vampires and arch-death-omancers within, named... Sanguine. Wait. What? Yes, the Daedric Prince Sanguine was there killing stuff in person. Apparently it was his way of apologizing for that drinking prank so long ago, as he genuinely wanted to try increase my skills. That doesn't stop me from trying to punch him but he's immortal (as if striking air) as usual.
In the depths of the place we find Njada, tied up. I hesitate trying to free her since she might secretly already be a vampire. While deciding, Sanguine quietly mentions "this would be a great opportunity to practice your destruction magic!" He has a point. Especially since the Arbiter's Helm lets me cast shock indefinitely, and I have a target who can both take the punishment and won't fight back... so...
Time to level up! (Lev 57)!
(Sanguine is super effective!)