Katherine "Kate" Kane (born January 26, 1990) is a wealthy individual and former aspiring-businesswoman, having become the acting owner of Wayne Enterprises, the founder and CEO of Gotham Pride Real Estate firm, and the owner and proprietor of the bar known as The Hold Up, before handing all of the aforementioned titles over to her successor, Ryan Wilder. She is the daughter of Jacob Kane and the late Gabi Kane, the twin sister of Beth Kane, the step-daughter of the late Catherine Hamilton-Kane, the step-sister of Mary Hamilton, the maternal cousin of Bruce Wayne, the ex-girlfriend of Sophie Moore, Julia Pennyworth, and Reagan, a close friend of Luke Fox and Kara Danvers, and a former member of The League.
After a family car accident caused by the Joker, Gabi and Beth fell into the river and were presumed dead after pieces of bones were found. Kate was resentful of Batman for not being able to save them. Eventually, Jacob married Catherine Hamilton and Kate met her step-sister Mary Hamilton. Kate decided to study at Point Rock Academy to gain Jacob's approval and join the Crows. There, she met and fell in love with Sophie Moore, who secretly started a relationship. Eventually, they were discovered and Kate was expelled for "homosexual conduct". Later, Kate trained with several masters around the world.
After returning to Gotham City to save Sophie from the Wonderland gang, Kate learned of Bruce's secret identity as Batman and took up his mantle, secretly operating as the vigilante known as Batwoman or simply the Bat, stylized by radio personality Vesper Fairchild as the Lady Crusader and the Bombshell Caped Crusader, as well as nicknamed by Sara Lance as Batlady. She is also stylized as the Scarlet Knight and the Bat of the Future. During the Anti-Monitor Crisis, Kate was revealed to be the Paragon of Courage. She and the rest of the Paragons defeated the Anti-Monitor and created a new universe with the help of the Spectre.
While Kate was on a flight home from National City after meeting with Kara over whether or not to destroy the piece of Kryptonite that she had, the plane's engine malfunctioned, causing it to crash. For a period of time it was believed that she was being held captive by Safiyah Sohail on Coryana, but it was eventually revealed that Safiyah never had Kate.
After this discovery, Julia Pennyworth discovered that body parts matching Kate's DNA were identified in Blüdhaven, leading to the belief that Kate had died in the crash. Despite this, Kate somehow managed to survive the explosion, despite having significant burns and a damaged larynx, but was soon taken captive by Roman Sionis, who enlisted Evelyn Rhyme to brainwash Kate into believing that she was Circe Sionis, effectively erasing Kate from her own mind. As "Circe", Kate operated completely as Roman's daughter, receiving plastic surgery and facial reconstruction operations to look like his late daughter, and becoming a model for his company, Janus Cosmetics, as well as his enforcer and right-hand in the False Face Society.
However, Kate was eventually freed from Evelyn's brainwashing due to the efforts of her twin sister, Beth. Having returned back to her former-self, Kate decided not to take back the mantle of Batwoman, as her successor, Ryan has earned the right to be Batwoman. Kate decides to leave Gotham in order to find her cousin, Bruce and bring him back.