Who is Brendan from Crank and what is their importance?

Brendan is the attractive life guard with whom Kristina flirts at Wild Waters. Kristina's mother approves of Kristina's relationship with Brendan because he is attractive. However, Brendan rapes Kristina during their second date. He is also hateful to Kristina and treats her in an abusive manner after the rape. Brendan's ugly personality continues to show when he at first insists that Kristina's baby is not his, and then refuses to help Kristina pay for an abortion.