John Constantine w/prep Versus Batman
Alright, rather than a KMC match, imagine this took place in an actual comic book. comic book logic and CIS apply. Constatine has a day prep and may use any sources he would logically go to for help, who may actually help him. (IE, he could ask Map for Batman's location, but no scenarios in which he just has the First of the Fallen kill Bruce for him). Batman has two hours of prep.
One week, and then Batman heads to London and starts hunting for him.
Can Constantine beat the Dark Knight?
(Additionally, he does not actually have to kill Batman himself).