Cassandra DuCharme is the Vampire delegate on the Interracial Council. Aaron Darnell is her former lover, and 2nd delegate on the Interracial Council. Cassandra is introduced in Stolen, and immediately showed an interest in Elena. However, once Elena is captured Cassandra attempts to seduce Clay by charming him. Elena witnessed this via a faulty spell cast by Paige Witherbourne, and has since ignored Cassandra's attempts at friendship. Cassandra recently began withdrawing herself from the world (called "becoming disconnected") and also has not been sleeping much lately. Both are signs that a vampire is in it's final years of "life".
Although Cassandra abandoned Aaron, she claimed that she knew he would survive the situation. She frequently shows small signs that she still is not over him. The first time Cassandra actually appears to be willingly helpful is in Industrial Magic, where she finally begins reembracing her responsibilities as vampire delegate for the council.