Faction Idea

[ElizabethLestrad]

This is more of a 'thinking out loud' kind of idea but I thought that since you have (I believe) two cases in quests where your exposing corruption with the Imperial Watch that a "Secret Police" faction could be made. For instance when you do the one with the Watch Captain shaking down the shop owners in the capitol and complete it it could do something like the Dark Brotherhood quest where a message prompts moments later saying some thing like.

 

'You begin to have the strange feeling that your being followed'

 

Then later when you do the Cheydinhall corruption quest, upon "successful" completion (murdering as opposed to turning in) a man appears (a "Lucien Lachance" if you will) and states that he has been watching your progress and proposes that you join the Imperial Secret Police.

 

They could have a secret headquarters underground or in a crypt in the center of the Imperial City and have quests where you spy on or assassinate subversives leading up to things such as raiding the Dark Brotherhood Sanctuary or hunting down members of the Thieves Guild and even assassinating the Grey Fox.