Dr. Poison was a notorious scientist from the Ottoman Empire who specialized in the field of toxicology and fluid dynamics. She was discreetly induced by the divine influence of Ares to create more deadlier weapons than those known. An admirer of her work was Erich Ludendorff, a general of the Imperial German army. He saw potential in Dr. Poison's work in poisonous gas and sponsored her research on behalf of the German military.
Dr. Maru's severe facial scars came due to accidental exposure to one of her own gases. She covers them with special plates shaped and colored to imitate human flesh, as was actually done during the time.
World War I
In the dying days of World War I, Ludendorff visited Dr. Poison in her research facility located in the Ottoman Empire to inspect progress on an even deadlier form of mustard gas (containing a hydrogen base instead of sulfur) capable of defeating conventional gas masks, which he hoped could still salvage a German victory in the war. Unbeknownst to the pair, one of Ludendorff's bodyguards was actually Steve Trevor, an Allied spy. He stole Dr. Poison's notebook containing her research and escaped by plane, thereby informing the Allies of her gas formula and plans to use it.
The theft of her notebook stalled her work considerably, but she none the less succeeded in creating the gas mask defeating poison gas that she and Ludendorff wanted. She also created "vials of energizer" gas for the general, that granted superhuman strength and durability if inhaled.
Ludendorff believed that deployment of Maru's new gas could win Germany the war, and tried to convince German military command to not sign the proposed armistice. They refused, and so Ludendorff and Dr. Maru used her latest gas on them, killing many high ranking commanders.
Ludendorff then organized a Gala, where he planned to demonstrate Maru's gas on the nearby town of Veld, as a show of power to the rich and influential guests who would be present, including Kaiser Wilhelm himself. They planned to deploy a huge amount of the gas via a prototype Zeppelin-Staaken long-range bomber over London, which Chief estimated would kill 7 million people.
Her gas was successfully deployed against the people of Veld, killing them all. At the airbase, Maru and Ludendorff oversaw the bomber's preparation. When Ares and Diana began fighting, Maru believed the base was under attack, and began destroying her lab and research so that it could not fall into enemy hands. Due to Chief also planting dynamite around the airbase, little to none of Maru's research is likely to have survived.
Dr. Maru tried to flee the base via car as it continued to sustain damage from the fighting of both Diana and Ares, as well as Steve's team and the local German forces. Ares used his telekinesis to summon her car as she fled and bring her before a furious Diana, who has just witnessed Steve's sacrifice. Diana lifted a German tank above her head and was going to drop it on Maru, but spared her, remembering her ordinance as an Amazon, and turning her heart back to love and compassion. Maru fled the base, and her ultimate fate is unknown.
As her title would imply, Isabel Maru is an exceptionally selfish, cold, and ruthless person, having a poisoned nature (described as a psychopath by Steve Trevor). Her willingness to fully wipe out the Allied Powers with her lethal gas rivals that of General Ludendorff himself. However, she seems to be relatively unambitious and utterly uninterested in the politics of war, instead being passionate about her scientific research in an artistic fashion. Her giggle after poisoning a room full of German officials implies that she is also quite sadistic.
However, Dr. Poison is also somewhat gullible, as Steve Trevor was almost able to deceive and get her to disclose her research to him. Her body language and tone after she discovers that Steve is interested in Diana, could also imply some self-deprecating bitterness about her physical condition.
- Gifted intelligence: Dr. Poison is exceptionally intelligent, which mainly extends to her considerable chemistry, toxicology, fluid dynamics, and lingual skills, making Dr. Poison General Ludendorff's most valuable ally.
- Expert chemist: Dr. Poison is a highly skilled chemist (notably more so than Slipknot), particularly in the field of toxicology and gaseous substances, as she was able to come up with a metahuman gaseous drug that extremely enhanced General Ludendorff's strength and durability, and also came up with a new and deadlier version of mustard gas (based on hydrogen instead of sulfur), against which gas masks would be useless. It should be noted, however, that Dr. Poison was given some covert assistance on her research from Ares.
- Multilingualism: Dr. Poison, apart from her native Turkish, also speaks fluent English (albeit with a Turkic accent), as well as the currently dead Sumerian and Ottoman Turkish languages, writing down her science notes in the latter 2.
- Human vulnerabilities: Dr. Poison's greatest weakness is that she is a human with no enhanced strength, speed, durability, or metahuman powers, therefore making her quite vulnerable to the physical attacks of stronger and more powerful opponents, hence she was terrified when confronted by Wonder Woman, and in mortal danger of the latter crushing her with a British tank. Indeed, Dr. Poison only survived that encounter with the mighty demigoddess because Wonder Woman chose to spare her.
- Gas pellets: Dr. Poison's personal fearsome invention (a new and deadlier version of mustard gas, based on hydrogen instead of sulfur) was contained in these pellets. General Ludendorff had her use a pellet against disagreeing German officers, and then load all remaining ones onto a military plane.