History
She call’s herself Jenny Wren after the British nursery rhyme of the same name:
“‘Twas on a Merry Time, When Jenny.”
Jenny claims to be Batman‘s first ever sidekick and to be the first ever Robin. She has stated that she failed “Zero Gauntlet” which is yet to be explain.
In reality Jenny, real name Anita Jean, was originally was an ally to The Escape Artist after hacking into his laptop with a decade-old cell phone.
The Escape Artist adopted Anita, but never treated her as daughter. Only really talking to her when needing something from her on his quest to bring down Batman.
Batman utilized this and became friends with Anita in order to help bring down The Escape Artist.
When Batman and Anita finally brought down The Escape Artist, he threatened to let the world know who Batman was really under the mask and that Batman along with Anita would loose everything.
After hearing this Anita shot and killed The Escape Artist, which then enraged Batman. She became distraught after Batman yelled at here and faked her death.
Anita then took on the identity of Jenny Wren when seeking her revenge on Batman after he took in other sidekicks and they took over the mantel of Robin. Which she never did.