Christel Dean was a friend of Clara Oswald. The two met in teacher's college and kept in touch in the years after. In 2014, Christel got a job at Ravenscaur School which she considered her "dream job". She became close to two of her pupils, Jack Irvine and Lucy Walker, showing them some of her selfies and being on first name terms with them.
In September 2015, Christel had begun to notice strange going-ons at the school, hastily leaving one night while leaving Clara a voicemail. As she drove, a group of possessed students caused her to crash. Trying to escape on foot, she wound up murdered by a Sea Devil. Her death would not be in vain however for Clara and the Twelfth Doctor soon arrived to investigate, halting the Sea Devils' agenda. (COMIC: Clara Oswald and the School of Death)