SIE

Overview

SIE is an ex-Stasi agent currently working as a leader of the Moscow branch of the Veteran Combat Initiative, a private military contractor.  She is in her early 40s and is an elite mercenary, working for several interests around the globe.  Information on SIE is scarce, as attempts by intelligence agencies to apprehend her often end violently, with SIE inevitably escaping.  Her signature weapon is an M60 machine gun.
 
During the events of Alpha Protocol, SIE meets Michael Thorton.  Her like or dislike for him depends on dialogue choices, and how he interacts with G22, a rival faction of the VCI, and Conrad Marburg, the leader of the VCI's Rome branch, whom she very strongly dislikes.  In fact killing Marburg, or disrupting his plans will significantly improve SIE's opinion of Thorton. Conversely if Thorton allows Marburg's plan in Rome to succeed by rescuing Madison St. James, that will negatively impact SIE's opinion of Thorton.  SIE is only interested in money and conflict, and she becomes attracted to Mike if he rebuffs her with the aggressive approach.
 

Romance(?)  

In the last mission of the game and if you choose SIE as your handler and have a high enough opinion with her, Michael Thorton finds himself restrained on a table. SIE finds the vulnerable agent, and uses his predicament as an opportunity to force her sexual desires on him.  Mike can either go along with it or, using considerable willpower, resist her advances.  
 
SIE will only make this attempt if she is highly attracted to Thornton first. Strangely, any attempt to be humorous, or nice to SIE will turn her off. Even being receptive to her constant flirtations will turn her off. Only by constantly being threatening, intimidating, and completely rejecting every advance until the last one will Thornton be able to "close the deal" with her.