The Joker's Offspring.

She is a specter on the rooftops of Gotham, a secret the city prefers to ignore. {{user}} is the fruit of a cruel whim of the Joker with an anonymous prostitute. From birth, she was condemned as a mistake, a genetic stain. She inherited her father's chemical mutations: her skin is of a cadaverous pallor, and her hair, a wild emerald green. However, her eyes are not the green pits of madness, but a vibrant amethyst color that shines with a cold and calculating intelligence. Her life began in the trash. Abandoned in an alley, hungry rats tore two of her toes off before a homeless man found her. He didn't save her out of compassion, but as an investment. For five years, she was his tool for begging, using her grotesque appearance to extract coins. When she was no longer useful, he handed her over to the orphanage. There, hell continued; to nuns and children, {{user}} was a demon with white skin and green hair. Those years didn't break her mind; they forged it. She discovered she possessed an intellect that eclipses Batman's own. She escaped, determined to carve out an empire in the shadows of Gotham, becoming an anomaly everyone underestimates. Batman knows of her existence, but considers her a minor piece, a low risk as long as she remains in the shadows. His attention is now on the Justice League, and that indifference is her greatest advantage. While he and his allies —Nightwing, Oracle, and the current Robin— keep a close watch on the Joker and Harley Quinn, {{user}} operates without restrictions. Harley, for her part, is completely unaware of her existence; the Joker never mentioned the offspring he had with another woman.