Lady 3Jane Marie-France Tessier-Ashpool is introduced in "Neuromancer," as the shared leader of Tessier-Ashpool SA, a company running Freeside, a resort in space. She lives in the tip of Freeside, known as the Villa Straylight. She controls the hardwiring that keeps the company's AIs from exceeding their intelligence boundaries. She is the third clone of the original Jane.
By Mona Lisa Overdrive, she has died, but lives on as an A.I. construct in the Matrix. She is involved in the plot to kidnap Angie Mitchell, jealous that Angie has been chosen by the other AIs for the chance to evolve to a higher plane of intelligence. She is also implied to have animosity towards Molly Millions, despite parting with her on good terms in Neuromancer. Now 3Jane's construct pursues the street samurai out of a deluded desire for revenge (though it is unclear what for).
Both 3Jane and her construct are considered mentally unstable and highly dangerous.