Who is Elody from Before I Fall and what is their importance?

Elody is one of Sam's three best friends. Although she belongs to the clique of girls, she is clearly lowest down on their totem pole. She appears to be the most sexualized of the four girls, and uses her sexuality to make men fall in love with her. Of course this plan doesn't work, and she is often left with a broken heart. While the other girls make fun of Elody's behaviors, Sam sees that she is vulnerable, fragile girl using sex to make herself feel more important.