Your favorite champion gets teleported into Gotham City
What happens?
What happens?
oh wait...
Pretty much every antagonistic character could be a batman villain.

Jinx meets joker and has a wonderful time
Where am I?
: "I think I'm in love."
: "I'm here to fight crime!"
Superman, Supergirl, and Power Girl all show up and carry Leona off to Metropolis.
Batman: "Hey, no fair!"
The kryptonians: "Rechargeable battery! We'll make it up to you!"
: "The time of bat man has come to an end."
: rolls around adorably
Robin: "Can we keep him?"
Batman: sigh "no."
: "So, if you don't mind my asking, what did you need these chemicals for?"
: "Oh, no reason. Just KILLING BATMAN!"
: "Umm, why not just have him chase me?"
: "He has gas masks you know."
: GASP
: "Hi there, Mr. Wayne!"
Batman: "Who are you?"
Zatanna: "Get back!"
Zatanna banishes Teemo back to hell
Batman: "I'm going to assume that was a close call. I don't want to get on your bad side."
: "You have to become a terrible thought. A wraith."
: training montage
: "So where is this batman character?"
: "Find the guilty."
: "Quit saying that!"
: "I hope he likes my t-shirt."
Batman: "It's nice."
: "Geez, do you sneak up on everyone?"
Batman: "Yes, it's my superpower. Why are the three of you here?"
: "Your friends sent us. Something about a trade for Leona."

Nananananananana bat trolllll BAT TROLLLLLL bat troll BAT TROLLL bat trolll BAT TROLLL
Every explosive action sound textbox to be replaced with CHOMP! as he takes a bite out of crime.
is now the batmobile.
: Darknesss...
Batman: Bitch, please.
:

I feel like
would end up joining the Justice League... or just end up moving to New York City -because no one in comics ever bats an eye when non-humans are in New York City.
Inb4 "Shaco finds his long lost brother"
Anyway...

He turns to a darker pastime seeking vengeance on those that murdered his family while he was on patrol. If he runs into the Bat, he treats him just like any other human standing in his way, tries to kill him, and fails. He then redirects his vengeful hatred towards him entirely for obstructing his personal justice, and attempts to corrupt him so that he can be justified in killing him as a criminal. He again fails, but in the fight learns of Batman's own personal loss and finding a kindred spirit turns away from the fight in order to aid the Bat in purging the city. All's well that ends well, Varus just stays out of Batman's way, and he out of his.
E.L.L Combos all of Batmans tech leaving him with nothing. Than kills the Batman.
Empower Lich Bane Leap Strike
Love: 
Batman has another cat stalking him
Gotham doesn't have to worry about criminals. They have much worse to worry about.

Buries Gotham in ice 
Nothing would happen, cause according to batman fanboys he is invincible and not even god could kill him.
Gotham City? You mean that crater over there?

teams up with batman and ults all Villains. Cat woman stays alive for Batman or natalya... Depending on what's Batman's mood.