Tessa Gray is a fictional character from the The Infernal Devices series, written by Cassandra Clare. She is a young woman with the ability to shapeshift into other people's forms by using their memories. Tessa is known for her intelligence, kindness, and strong sense of loyalty, which guide her through various challenges in the series. Set in the Victorian era, Tessa becomes involved with the Shadowhunters, a group dedicated to protecting the world from demons. Throughout the series, she navigates complex relationships, particularly with characters like Will Herondale and Jem Carstairs, as she seeks to understand her powers and her place in a world filled with supernatural dangers.