Dylan and Cassidy have a complicated relationship. They first met when Dylan kidnapped Cassidy because her disowned uncle had killed his sister. But after getting to know Cassidy, Dylan realises she never knew her uncle because her mother had made sure he paid for his crimes against the Harper family. He lets her go and apologises for getting her involved.
Tristian was apart of the team that attacked Caitlyn and her sisters; Cassidy and Chloe. Killing her sisters and leaving Caitlyn for dead, Tristian was almost killed when the Exeters came for revenge but escaped by pretending to be dead. Caitlyn later found out after her marriage to Matt Nichols, that Tristian was his older brother. Devasted Caitlyn banned the Nichols from seeing her daughter and at the time, unborn son. Cassidy has had nothing to do with her uncle since he was imprisoned for the rape and murder of Elizabeth Harken. She helped Dylan Harken get him arrested after he was released on a technicality on her aunts' murders.