The underground cavern was massive, and far below I could see a small fort guarded by a handful of patrolling Thalmor. The bridges leading down had broken and were replaced instead by... lit floating torches? *Sigh* Someone likes jumping puzzles. A few hops, skips and jumps down and I was sniping the clueless guards. One shot, one kill.
Jumping puzzle with invisible platforms. Thanks crazy Thalmor!
The interior wasn't much better defended, and I managed to catch the guard captain and his "adventuring team" sitting at dinner. Shot him in the head and rushed the rest. Half of them were dead before they could even stand and draw weapons. The other half didn't fare much better. In their cheese filled basement below I did the Thalmor a favor by exploding their skeever infestation, then proceeded up stairs and stumbled upon a magic class.
Ultimate stealth: Casting destructive ritual magic in the center of an enemy magic class and not being detected.
After dealing with them and some fire eles, I made my way to the top of the tower to deal with the head honcho only to find, he wasn't there. A note and key suggested he went into the crypts below, and so after a lot of looking I finally found a passage behind one of the many tapestries that led even deeper underground... People just love digging too deep.