Who are the best characters to include in a Poison Ivy x Batman fanfiction aside from them?

Edward could be a good addition. Since he has his mind - reading ability, it could create some interesting interactions with Alice's visions. Also, Bella could be included as she has a connection to both Alice and Jasper through Edward. Her human perspective could add a different dimension to the story.

Well, Kikyo is an obvious choice. Her connection to both Inuyasha and Naraku is deep. Her presence could create a lot of tension, especially since Kagome is often compared to her. Shippo could also be in the fanfiction. His cute and innocent nature could contrast with the dark nature of Naraku. And Kaede, the old priestess, could offer her guidance and wisdom regarding the strange relationship between Naraku and Kagome.

Lois could be a great addition. Her relationship with Peter and her reactions to his antics with Quagmire can add a lot of drama. Also, Cleveland. His calm and collected nature contrasts with Peter and Quagmire's craziness. His interactions with them can lead to some really funny moments.

I think Hinata could be a great addition. He could be the comical sidekick who always gets into funny situations and in the process, either helps or hinders Usui and Ayuzawa's relationship. Another good character could be Ayuzawa's mother. Her presence could add some family drama, like she might not initially approve of Usui for her daughter.

The Joker is an obvious choice. His relationship with Harley Quinn is complex and his chaotic nature can add a lot of drama to the fanfiction. Also, Poison Ivy could be included. She has a strong friendship with Harley, and her plant - based powers can create interesting scenarios when combined with Batman's detective skills.

There's also 'The Ivy - Bat Alliance' fanfic. It starts with an unlikely alliance between Batman and Poison Ivy against a common enemy in Gotham. As they work together, their relationship blossoms in unexpected ways. The writer creates a vivid Gotham setting and the dialogue between the two characters is both sharp and full of unspoken emotions.

Jacob could be a great addition. He has a complex relationship with Bella in the original series. In fanfiction, his interactions with Charlie could be explored further. For example, how Charlie reacts to Jacob's wolf - shape - shifting abilities and his love for Bella.

Santana could be a great addition. She could be Rachel's best friend who gives her brutally honest advice about married life. Like when Rachel has a fight with Jesse, Santana would be there to say something like 'Girl, you need to put your foot down or he'll walk all over you.'

Edward could be included. He could be Emmett's rival in a sense, not in a romantic way towards Rosalie, but perhaps in a career or talent aspect. For example, if Emmett is into sports, Edward could be a really good athlete too. This creates some friendly competition between them. Also, Leah could be a character. She could be Rosalie's coworker and through their friendship, Leah could influence Rosalie's relationship with Emmett in different ways.

Raphael could be a character to include. He might initially be skeptical or even opposed to Leonardo's relationship with Karai due to her past actions. His presence could add some internal conflict within the group. Also, Shredder could be in the background as a looming threat, which could heighten the tension in their relationship as they try to keep it a secret from him.