Kati

From Rom Com

Kati is the cousin of Aimee and locked in competition with her friend Alex. She and Alex come up with a bet to see who can seduce more people, leading her to seduce Nick, Dylan, Hallie, a horde of other people, and eventually Alex himself. Kati's tentative name is Emily.
Kati appears in the following scenes:

Opening
Alex and Kati's Bet
Graveyard Seduction
Photo Montage
Kati/Dylan Seduction
Finding the Pictures
Dinner Sincerity
The End (Alex and Kati)