Save the Cheerleader, Save the World.
As other characters were uttering this line to begin the first half of the series, they were referring to Claire Bennett.
A confused 16-year old, Claire is indestructible. She has her friend, Zack, video record her catching on fire and jumping off high structures in order to document her incredible healing power.
But where does it come from? She's the adopted child of the mysterious Noah Bennet and his wife, but we later discover her biological father is Nathan Petrelli - and she was given to Mr. Bennet by the father of Hiro Nakamura after she was supposedly killed in a fire.
Mr. Bennet holds on to her for safe keeping until she develops her powers and he's forced to help keep her away from his devious employers.