During their sessions Brock revealed to Dr. Kafka that he was once bonded to an alien symbiote and became Venom but Spider-Man separated them and sent the symbiote into space. However, Ashley Kafka believed that this was just a delusion created by Eddie Brock after Spider-Man's constant persecution of him.
Ashley Kafka also treated Cletus Kasady when he was brought to Ravencroft.
Baron Mordo later re-bonded the symbiote to Brock turning him into Venom again. Venom then fought off the guards. As Dr. Kafka went to see what was going on she saw Venom and realized that Brock was telling her the truth. Venom then escaped Ravencroft.
When Ashley Kafka saw on the news that Venom was fighting Spider-Man at Stark Enterprises she went to Stark Enterprises to talk Venom out of what he was doing. However, her attempts to stop Venom failed and Venom and Carnage were able to escape Stark Enterprises with the Inter-Dimensional Probe. Venom and Carnage then gave the probe to Baron Mordo so he could use it to free Dormammu from the Dark Dimension.
Venom then stopped working for Baron Mordo and attacked J3 Communications. Venom then fought Spider-Man and Iron Man. Ashley Kafka was at J3 Communications while this was going on. Dr. Kafka told Brock to fight the symbiote's control over him. However, Venom grabbed Ashley Kafka and got away.
Venom then brought Ashley Kafka to Ravencroft. While at Ravencroft, Ashley Kafka and Eddie Brock revealed that they loved each other. Brock also told Ashley that he could feel the symbiote getting stronger and begged her to help him.
While Eddie Brock was recuperating Carnage attacked New York City. Ashley Kafka went to help Carnage because he was her patient. Curt Connors tried to talk her out of going saying that Carnage was too dangerous. However, Ashley Kafka went anyways. When Ashley Kafka found Carnage he was fighting Spider-Man. Carnage then drained Dr. Kafka of her life force so Baron Mordo could use it to free Dormammu. Mordo then teleported Carnage and Dr. Kafka to his lair. Spider-Man and Iron Man asked Brock where Mordo's lair was. However, believed that Spider-Man and Iron Man wouldn't stand a chance against Carnage, Mordo, and Dormammu and re-bonded with the symbiote to help them save Ashley Kafka.
As Spider-Man, Iron Man, and Venom arrived at Mordo's hideout they attacked Carnage and Mordo. Despite their efforts they failed to prevent Mordo from using the Inter-Dimensional Probe to bring Dormammu to Earth. As Venom fought Carnage he found Ashley lying on a slab of rock and walked up to her. Ashley saw that Brock had re-bonded to the symbiote to save her and she made Brock promise that he would use his powers to fight injustice.
Dormammu ended up being freed from his dimension and came to Earth. Spider-Man was able to reverse the polarity of the Inter-Dimensional Probe. This caused Dormammu to be sucked back through the portal. However, Spider-Man was unable to use the probe to close the portal. Iron Man realized that Dormammu had created a link between Carnage and the portal and knew that because of this the portal would only close if Carnage went through it. As Spider-Man aimed the Inter-Dimensional Probe at Carnage he started getting sucked into it but held onto a stalactite to keep him from going through. Carnage knew that he couldn't hold on forever and grabbed Ashley Kafka saying that if he was going to another world he wasn't going alone. However, Venom sacrificed himself to save Ashley Kafka. Brock managed to save Ashley but in the process he and Carnage were sucked through the portal. Spider-Man was able to close the portal and Iron Man smashed the Inter-Dimensional Probe.
As the sun started to rise Spider-Man took Ashley Kafka back to Ravencroft. While there Ashley told Spider-Man that Eddie Brock couldn't stand to live as a monster in a world of men. Dr. Kafka also told Spider-Man that he hoped Brock would be able to find peace in the other dimension he was now in. Spider-Man replied that he hoped she was right and left Ravencroft.
In the comics
Ashley Kafka was the founder and head administrator of the Ravencroft Institute for the Criminally Insane. Whether she was the administrator of Ravencroft or just a psychologist was not specified in Spider-Man: The Animated Series.
While Ashley Kafka worked at Ravencroft she treated many criminally insane supervillains including Electro, Vulture, Carnage, Chameleon, and Doctor Octopus.
When Dr. Ashley Kafka's success rate came into question, she was replaced by Dr. Leonard Sampson as director.
She was killed by one of her patients, Massacre, during his escape.
Almost a year later Ashley Kafka was cloned by the Jackal (Ben Reilly) so she could get Spider-Man to agree with what the Jackal was doing.