Captain Aquilius

 is the leader of the Wizard Guards hired by Calcelmo, and resides within Calcelmo's Tower. The Dragonborn encounters him during the Thieves Guild quest Hard Answers. After taking a rubbing of Calcelmo's Stone using a piece of Charcoal and a Roll of Paper (both of which can be found in plentiful supply in the room right before the stone), Captain Aquilius enters the tower with three Wizard Guards. The captain is a bit stronger than the other guards, but drops the exact same loot they do - a full set of steel armor, Calcelmo's Laboratory Key, and Dwemer Museum Key.

Quests

 * Hard Answers

Quotes
Captain Aquilius: ''Alright men, spread out and search the tower. No telling who- or what- we're dealing with here.''