Trevor is the mortal boy Luce Price liked. They mildly dated and kissed once once. Whenever she had a moment with a boy the "shadows", which are the Announcers, Luce called them, would ruin it for her. As she and Trevor kissed, the whole scene erupted in flames and Trevor was killed. Luce's hair was burnt and her mother had to cut it. Luce would never forget the day that Trevor was killed at her expense. Luce was certain that the shadows killed him, but no one believed her. Later she was sent to Sword & Cross, where she met Daniel Grigori and others, and the story begins. Luce once mentioned, in book one, when she hardly knew Cam, that she knew Trevor as much as she knew Cam at that time. Other than this, Trevor isn't mentioned in the books, except for the times when Luce blames herself for all the deaths. Luce's affection to Trevor is nothing compared to the love she shares with Daniel, and the friendship with her fellow angels.
In the upcoing Fallen movie, the actor, Leo Suter is portraying Trevor. In the movie, there is going to be Trevor's ex-gilfriend, Rachel, who is portrayed by the actress, Norma Kuhling, will be present at the party when Trevor dies.