Jace Herondale is a fictional character from the popular book series, The Mortal Instruments, written by Cassandra Clare. He is a Shadowhunter, a human with angelic blood, tasked with protecting the world from demons and other supernatural threats. Jace is known for his exceptional fighting skills, charm, and complex personality, often struggling with his identity and family legacy. Jace is the son of Valentine Morgenstern, a notorious villain in the series, and Clary Fray is his love interest. Throughout the series, Jace develops strong relationships with other characters, including his adoptive siblings, Isabelle and Alec Lightwood, as they navigate the challenges of their world together.