OK, I don't know too much about Batman, but I know somebody who does, so they should be a useful source of info if there is anything I can't think of.
Then again, he DOES try to make all the characters kid-friendly... Not my style, obviously. I'm all about dem blood, guts, and destruction! MUHAHAHAHAHAHAHA.
Kane peeked inside the abandoned house where the noise had come from. He had been on a night time stroll when he heard something strange inside here. He slowly tiptoed in and closed the door behind him, then looked around. His eyes widened in shock. Everywhere, there were bats. Lots of them. They stared at him, looking scared. They were obviously Vampire bats.
Kane had done extensive research on these creatures. They, like all creatures, interested him. But what were they scared off? I mean, they had a fine set up here. Nothing seemed to bother them and they probably didn't have to worry about predators. They most likely fed off of stray cats and dogs, so they shouldn't have anything to worry about.
"So why are you little guys so scared..." He muttered to himself, "And why are you even in Gotham, or North America in general?"
SCREECH!
Kane covered his ears as a bat somewhere screeched in pain. It sounded like it had come from the back. He slowly tiptoed towards the sound and cracked open a door, peeking inside.
The sight he saw almost made him gasp from the shock, but he managed to cover his mouth. At an operating table stood a man that Kane recognized well.
It was The Joker, giggling and laughing.
"Oo hoo hoo! This Langstrom guy did a great job making this serum formula! Too bad he meant for it to be for fixing hearing. He woulda made a GREAT business partner! Too bad Harley got tired of him crying over his wife and killed him! Now I'm stuck doing this because those bozos don't know HOW TO DO ANYTHING!" Joker shouted the last part, scaring Kane, and making him fall over, through the door, and right at the madman's feet.
"Hey Mr. J, I think people are really startin' to worship ya! They're just fallin' at ya feet these days!" Harley Quinn said, laughing.
"Well well well! I think I just found my test subject!" Joker laughed as he injected Kane with a bluish serum.
"AHHHHHHHHHH!" Was the only thing that escaped Kane's mouth before he blacked out.
"Any idea what's going on, Batman?" Officer Gordon said.
"Most likely? Someone is trying to draw me out. For what reason, I don't know. But I'm going to fi-" The Dark Knight was cut off as someone came out the window as though thrown. The seemed red white and black from a distance. Batman knew immediately who it was. He caught Harley Quinn just before she hit the ground. She has a long cut across her chest and blood running down her shirt.
"Have a present, Batman! From your new friend! Hehehehe!" A loud, scratchy voice called out.
"Who are you?" Batman called out, laying Quinn on the ground. A dark figure flew down and landed in front of them. Gordon stepped back, shocked. A man with fur covering his body and wings for arms stood in front of them. He had red eyes and fanged teeth, like a vampire bat. His tongue came out and slowly licked blood off his lips.
"I'm... well, I don't really know! Hehehehe! But I know this much: Blood is goooooooooooooooooood! So delicious... it makes me want more... oh, but I must go now! I really wish I could stay, but that'd get me arrested!" Then he was gone, faster than even batman could see, screaming into the night, yelling about his hunger for blood.
"Batman... What WAS that?" Gordon said in shock.
"That... was a Manbat. Definitely not the original. And he wants to cause a lot of trouble. I have to stop him before he can do any major damage." Then Batman was gone as well.
Sorry it was so short! I just needed SOMETHING for a beginning!