Who is Danny from Annie's Baby: The Diary of Anonymous, a Pregnant Teenager and what is their importance?

Denny is the father of Annie's child. When Annie tells Danny that she's pregnant, he immediately says that the baby isn't his. When Annie's mother pushes the issue with him, he tells her that the entire football team is ready to swear that Annie is a tramp and that they've all had sex with her. As cruel and heartless as Danny is, Annie has a difficult time getting over him. There are no indications that he has a difficult time getting over her.