The Pale Lady
Another in a short list of compelling female Batman villains, Natalia Knight, Nocturna, was created in 1983 by Doug Moench, Don Newton, and Gene Colan for Detective Comics #529. I am surprised I hadn't heard about this character more, or why she hasn't been used more frequently, as she ticks off a lot of boxes character-wise.
An orphan, like our hero, Batman, Natalia Knight is adopted by a Gotham mobster. She attempts to turn away from her criminal family and becomes an astronomer, working at Wayne Enterprises. Another in a long line of science-based Batman villains, Natalia is a victim of a lab accident (obviously), which essentially turns her into an albino. After this, she rejoins her adoptive brother Anton Knight and his inherited crime family. The two of them start a career of breaking and entering, and burglary. So, to recap, Nocturna is a female thief, and gangster, a scientist, and an accidental monster, and creature of the night. On the surface, she appears to be all the things a classic Batman villain could be rolled into one character.
The rest of her character history is wild. There is a weird love triangle between Nocturna, her adoptive brother the Thief of Night, and the Batman. Natalia Knight tries to adopt Jason Todd for some reason, and becomes an anti-hero (because of course she does). She also assumes the leadership of Black Mask's False Face Society, and was a member of the Injustice League. She's been a foil for Batman, Robin, Stephanie Brown, and Batwoman.
After the New 52 reboot in 2011, this character was retconned by Marc Andreyko and given vampire powers for some reason. This appears to be unnecessary. Still an astronomer with ties to Anton Knight, her name was changed to Natalia Mitternacht (midnight in German), and she becomes primarily an antagonist of Batwoman. The retcon gave Nocturna hypnosis powers, and a long history of multiple marriages all ending with dead husbands, but her light sensitive albinism seems to have disappeared. This character has more in common with Carmilla tropes, and a serial killer MO, obsessed with the blood of her victims, like Elizabeth Bathory myths.
This character has appeared in the Batwoman television series. There will be a Natalia Knight in the new upcoming Bruce Timm Caped Crusader show.
I like the overall feel of this character and feel like she has potential to be a terrifying addition to Batman's more notorious rogues gallery. I would keep the mobster ties and relationship with Anton Knight. A weird brother/sister relationship contributes to the creep factor.
I would also keep the scientific accident that fundamentally changes her physiology, much like other villains Clayface, Manbat, Mr Freeze, and Poison Ivy.
The astronomy background is a must, and I encourage the serial killer/Elizabeth Bathory angle, perhaps emphasizing kills corresponding to phases of the moon or astrology signs, like the infamous Zodiac Killer. I'm not jazzed by the vampire thing, it would be more interesting to have her be just a weird albino with a fascination with blood. Perhaps she believes bathing in blood helps her condition. Perhaps the changes to her skin chemistry requires certain proteins so she doesn't burn up in the sun, and blood is the best sunscreen? This has parallels to Cornelius Stirk.
I would like to see this character reimagined as a serial killer astronomer who has to turn to her adopted mobster brother to help hide her crimes. A story involving a character like this would play with murder mystery, occult, and mobster crime tropes all of which are the best kinds of Batman stories.