I entered the final instance of the “Means to an End” quest where I received the following expected results:
After placing the horn:
Niilo Wolfskinner: There it is. Romke’s horn! Grab it and cut down these weaklings.
Niilo Wolfskinner: Out of my way, woman!
Eir Stegalkin: The corruption is stronger than we thought. The horn is defending itself!
But once I defeated the Sons, the game seemed to think that the battle was still going on. The battle music continued to play, a couple of bears moved over to a wall and stared at it as if some enemy that only they could see was standing behind it, and when I talked to Eir Stegalkin, she responded with something to the effect that “No time to chat, finish this battle!”.
H.