While Ares and Germany’s real-life General Erich Ludendorff may serve as the two biggest adversaries in Wonder Woman, they’re aided by the brilliant, deadly chemist named Isabel Maru, or as she’s referred to by the British army—Doctor Poison.

While not as widely known as the God of War or other longtime Wonder Woman baddies like Cheetah and Circe, Doctor Poison is actually one of Diana’s oldest villains, making her debut back in 1942’s SENSATION COMICS #2. Like most baddies of the time she’s a wartime villain—a dark scientist with a knack for crafting cutting edge toxins. As such, she’s remained frighteningly relevant and has continued to act as a dangerous threat to Diana, Steve Trevor and the rest of the DC Universe since her debut…albeit with a few identity revamps along the way.

The original Doctor Poison was the Chief of the Nazi Poison Division and was in league with a squadron of German spies. (Remember, while she’s a WWI-era scientist in the movie, in the realm of comics she debuted during WWII.) This early version of Doctor Poison wore a mask and large bodysuit that made her gender ambiguous until the end of her debut story, where she was revealed to be an Asian princess named Maru—a surname that has stuck with the character ever since. While her initial poisons weren’t quite as lethal as the movie’s mustard gas (this was the Golden Age, after all), they were still destructive. Her debut toxin was a drug called “Reverso,” which altered victims’ brains to do the reverse of what they were told. That’s bound to create problems when an army is ordered to advance, retreat or stand down…or, as seen in the story, when their commanding officer orders them to “dress their ranks,” prompting an unexpected striptease.

Maru was eventually captured and forced to give up the antidote, but made additional early appearances and eventually teamed up with seven other female heavies—including Giganta and Cheetah—to form Villainy Inc., one of DC’s earliest super-villain teams.

After CRISIS ON INFINITE EARTHS changed the DC Universe, Doctor Poison was eventually reintroduced to the pages of Wonder Woman. Only this time, she was a new scientist named Marina Maru who was the granddaughter of the original Doctor Poison. Like her grandmother, Marina also wore a full bodysuit and mask that made her gender pretty ambiguous. Her lips had been hooked back into a psychotic-looking grin, and she seemed to make greater use of syringes, wielding them almost as a weapon. In other words, she was nothing short of a nightmare.

The Post-Crisis version of Doctor Poison was a startlingly effective update on the character who in her debut story revealed what had happened to her grandmother and her Reverso poison. Ultimately, the poison had infected its creator, reversing the earlier Maru’s growth patterns and causing her to grow younger at such a rapid pace that before she could repair the damage she’d grown too young to remember the antidote. She eventually regressed into a fetus and disappeared. As her granddaughter puts it, “Horrible end… Wonderful poison.”

While the second version of Doctor Poison used elements of body horror to great effect, the third took its inspiration from a horror of a different type: terrorism and chemical weapons. This Doctor Maru was the daughter of Russian scientists whose parents were branded terrorists by Russia after it was discovered that they had been in contact with the United States about working with them to develop biological weapons. Maru’s parents had refused, but nevertheless they were arrested, thrown into a Siberian prison and eventually died, leaving their daughter behind to seek revenge against the U.S.

This take on Doctor Poison shared her predecessors’ skill at developing deadly toxins, but lacked their flamboyance. She never donned a costume, instead operating in regular clothes. However, her military ties made her a good transition to the current and most different version of Doctor Poison to date.

Found in Greg Rucka’s Wonder Woman Rebirth comic, this Doctor Poison isn’t a doctor at all—she’s a colonel who leads a private paramilitary group known as Poison. While she’s also named Marina Maru, Rucka’s version of the character is more of a soldier than a scientist. However, she still deals in chemicals. In the recently collected “Year One” storyline, her family helps create a bio-agent that causes its victims to fly into a rage, killing anything in sight.

While notably different than all the other characters who have shared her name, Colonel Maru still looks the part. She even recently donned her version of the suit and cowl worn by the second Doctor Poison, complete with the caduceus over her eye. Interestingly, this version of Maru is also scarred, a trait she shares with the movie’s interpretation of the character.

Played memorably by Elena Anaya, our big screen Doctor Poison is now called Isabelle Maru, and may be the most frightening version yet. With her primitive facial prosthetic and raspy voice, both due to the horrific scarring one has to assume was a result of her work, she comes off as vulnerable and haunted. However, that vulnerability helps mask the real darkness she hides within. She’s a reinterpretation of the character that could only work in the film’s WWI setting, and yet with chemical warfare still very much a reality, she’s extremely identifiable. And as viewers of the film know, she’s still on the loose.