Ha I don't know why but this idea just popped into my head at random today even though I haven't seen the original Batman Animated Series episodes in 8 years. I am just putting this out there for anyone who ever was a fan of the original cartoon series and will also say this RP involves the Joker and does get a lot darker than the original cartoon series (think the movie "Return of the Joker," along with the Nolan movie "The Dark Knight").
Batman- Sixshot
Joker- VM
Harley Quinn- VM
Jane (child, OC)- VM
Poison Ivy- VM
Boy (OC)- Sixshot