When Major Kraus murders Andre Toulon's wife Elsa Toulon, he puts her soul into a doll that he had made, but she was defenseless in this form so he used medical leeches that he found in jars and put them into her mouth, she then became Leech Woman. After Lt. Eric Stein is murdered by her leeches, Major Kraus gets angry and starts shooting jars of medical leeches that Toulon had used.
Leech Woman has the ability to vomit out leeches at will that will suck the blood from her victims. The leeches seem to be a magical power or poisonous since they were created by Andre Toulon. She can summon them whenever she chooses. On one occasion when she helped to kill Neil Gallagher, a giant leech came out of her mouth.
When Robert Toulon rebuild Leech Woman, after she was killed, Robert added some adjustments to the leeches. They're not just poisonous, but also electric and can shock incredible, extreme volts of electricity to the enemies. Robert gave a telescopic neck to her and a tank on her back where the leeches are contained.