Jane Doe

Origin 

While in Arkham Asylum, Waren White bribes his psychiatrist Dr. Anne Carver, into having him transferred to a minimum security prison but unbeknownst to White, Carver is actually Jane Doe. Jane had studied Dr. Carver's mannerisms before she killed the real Dr. Carver. Jane Doe had destroyed all of Dr. Carver's paperwork on her and she agrees to help White on making a transfer in a manner of speaking. As it turns out, Dr. Jeremiah Arkham is aware of Jane's activities so he instructs her to transfer White's sanity to whole new level of insanity. Arkham's vindictive motivation draws from the loss of his pension which was brought on by White's corrupt business practices at his brokerage firm. Jane captures White and locks him in Mr. Freeze’s subzero temperature cell. Jane assumes that White will die in Freeze's cell thus allowing her to claim White's identity and steal his ill begotten funds but this doesn't work out since White survives Jane's attempt to murder him. Now, White becomes the Great White Shark and Jane has a new enemy. 

 

House of Hush

  
While the courts debate on whether or not Harvey Dent is capable of standing trial, Kate Spencer aka Manhunter has a sit down with Jane Doe. Kate offers Jane a deal that if she testifies against Two-Face's insanity plea then Doe’s sentence will be reduced to life imprisonment and Kate will take the death penalty off the table. Doe tells Kate that she’ll have to think about it because the night before this meeting, an Arkham guard led Doe to Two-Face’s cell, where he has a counter offer waiting for Jane.  Hush also pays Jane a visit at Arkham as  Bruce Wayne. Hush influences the parole board at Arkham to release Jane Doe so that he can use her in his plan against Batman but she later escapes because she knows how Hush rewards his allies. 
 
As it turns out, Jane Doe had killed Jeffrey Carter, Hush's impending hostage that he would use against Batman. Jane figured that if she posed as Carter then she would be captured thus allowing her to get close to Hush and steal Hush's persona as Bruce Wayne. Jane's plan was to become Bruce Wayne and take control of a multi-billion dollar industry. Unfortunately, Batman arrives and puts an end to her plan. On the bright side, Jane maimed Hush's face so severely that Hush could no longer pose as Bruce Wayne ever again or anyone for that matter.           
 

Abilities

Through constant and obsessive analysis of another individual, Jane herself, becomes that person once she murders and wears their skin. Not only can she accurately copy body language and speech patterns, but can completely imitate their thought patterns and behavior.