That girl is hella crazy!!! I never expected a character like her to make an appearance. It was a great chapter though I was somewhat let down that Keima only had a cold. I thought it was something.... more.
Rawr, I like how they are not giving away any clues to which girl it might be, keeping the suspicions and guesses till the last moment. As it is now, you could as well throw a coin and the chances of guessing would be the same.