Originally posted by TreasureCat:

Oh hey, I was wrong based on the event wiki. I missed this story event because of the way my progression happened, but you can get either trolls or a skeleton/draugr attack where you're at right now. Unfortunately, those are the only two options, and who knows if they're weighted evenly.

Considering I've had like 16 troll attacks total, and ONE draugr attack, I think the weights might need to be adjusted.

Honestly the draugr fight was much more fun anyway, I actually died during that one.