Poison Ivy

Ivy later escaped Arkham and clashed repeatedly with Batman, seemingly obsessed with him as the one man she could not control or manipulate. Her crimes often made use of methods of mind control using plant-based pheromones or toxins, taking advantage of her own immunity to poisons. However, Ivy continued to transform over this period, acquiring more and stronger powers relating to plants, including the ability to make them grow incredibly quickly. In the process, her priorities changed, and she became an eco-terrorist, attacking those who polluted or otherwise harmed the environment. Her former professor, Doctor Woodrue, now transformed into a plant-being himself, returned and proposed an alliance to conquer the world, but ultimately she turned on Woodrue and helped Batman defeat him.

When Gotham City was nearly destroyed by an earthquake and largely evacuated, with various criminals and factions taking over what remained, Ivy claimed Robinson Park, turning it into a green sanctuary for orphaned children. Clayface attacked and imprisoned Ivy, claiming the park for himself, but Batman freed Ivy and, acknowledging that she provided a good home for them, allowed the children to remain with her for the time being. After Gotham City was rebuilt, there was a standoff between Ivy and authorities that Batman tried to negotiate peace with, but it appeared it would end in violence until one of the kids was accidentally poisoned by Ivy and she surrendered in order to get the child life-saving treatment.

Ivy joined fellow villains Harley Quinn and Catwoman as the Gotham City Sirens. They pulled heists, with Ivy using the money to aid environmental causes, but also opposed criminals, helped each other, and became friends. Ultimately, an angry Harley sought to kill The Joker for the wrongs he'd done her. She broke into Arkham Asylum, triggering a riot that Ivy and Catwoman got involved in. Batman put it down, arresting everyone but Catwoman. Ivy broke into Harley's cell to kill her for getting them captured, but took pity on her and offered to free her if they killed Catwoman, who left them behind. But Catwoman revealed she'd been using her connection to Batman to prevent them from being arrested because she saw good in them. As Batman closed in, Catwoman helped Harley and Ivy escape a final time.

After spending more time together, Ivy and Harley saw their relationship develop from friendship into a romantic one. For both of them, it was the first time they had experienced a relationship on equal terms instead of being with a manipulative, self-centered partner. While they have acknowledged that neither is the type to settle down, at least not at the moment, and they often go in different directions, their feelings for each other are powerful and if one needs the other, they will be there. For example, when Ivy was traumatized by inadvertently killing innocent people and reacted by mind-controlling the entire world with the exception of Harley and Catwoman, Harley was instrumental in reaching her, convincing her to release everyone's mind and get help.

More recently, Ivy has walked the line between villain and anti-hero. She has worked with the Birds of Prey, helping them on missions, but she also poisoned the other team members to force them to attack corrupt companies she wanted to destroy for polluting the environment. Ivy follows her own moral code, which values plant life as much as or more so than human life. She has shown that she is linked to the Green, the force that unites all plant life and has the Swamp Thing as its champion, but she is independent from it; violence is not the Green's way, but Ivy has made it clear she has no problems using violence when she feels it's necessary. Ultimately, the only predictable thing about Poison Ivy is that she will look out for the environment... What no one can be sure of is how.