Kelly Hayes was a dhampir who attended Amberwood Prep as a junior with Lee Donahue. She had her throat slit and was killed by Lee when he was attempting to turn back into a Strigoi. Lee said that as a dhampir, Kelly was stronger than him and to kill her, he had to get close to her. He did so by becoming her boyfriend.
Kelly was mentioned to be an excellent athlete and "participated in nearly every sport that Amberwood offered and had been exceptional at all of them."
After her death, Amberwood made a spread in Kelly's honour. Most of the photos were of her playing sports but there was one picture of her at the prom. She had Lee by her side as her date and this was what helped Sydney identify Lee as an enemy, and it was what prompted Lee to take action and attempt to kill Sydney to become Strigoi once more.