I continued doing Thieves quests in order to improve the Guild. I did enough for the remaining two cities, Markarth and Solitude, and started the special missions.

Markarth's involved retrieving a stolen item. While I was traveling, I fought an Ancient Dragon. With the Razor, I instakilled it with the first strike. B) I arrived at the location to find a regular looking shack. The item was nowhere to be found. Then I noticed a secret button that moved the bookcase to reveal a SECRET PASSAGE. There was an entire underground cave complex underneath.

I returned to the Guild after completing the two quests and was made Guild Master. Neat.

I fast traveled to the College (I don't even remember why) and fought yet another Ancient Dragon. I didn't manage to instakill it this time though. I talked to some of the people, one had a special mission now that my Illusion was high enough. I had to use some spell that allowed me to see magic books hidden throughout the College. When I returned all four to him he gave me a Master-level Illusion spell, and he rest were available for purchase.

Next I went back to Blackreach to gather up some more Crimson Ninroot. I took them back to the dead scientist's colleague and gained an ability that made it so I might sometimes mix two potions instead of one. I never use Alchemy so this isn't very helpful, but whatevs.

I'm out of side missions yet again, so I think I might set out to find the Dark Brotherhood.