in Jace's body then allows Simon to stand in high sun with no risk of burning, unlike all other vampires who cannot. After Max Lightwood's death, Isabelle (Max's older sister) becomes distraught, blaming herself for not listening to him and for not being there for her little brother. She refused to see anyone, finally allowing Simon to come in. Simon comforts Isabelle, trying to convince her that Max's death wasn't her fault, and ends up sleeping next to her, much to his surprise, although they do nothing sexual. Towards the end of the third novel, Raphael demands Simon's death in exchange for his clan's assistance for the war; Raphael believes Simon's Daylighter powers make him too dangerous to remain alive. In order to protect him, Clary draws the Mark of Cain on Simon, which prevents him from being harmed by anyone and also curses him, marking him as a wanderer for eternity. In City of Fallen Angels, a conflicted Simon tries casually dating both Isabelle and Maia. When the girls find out, they both leave him, and he is alone once more. However, by the end of the book it is clear that a deepening relationship is forming between Simon and Isabelle. In City of Lost Souls, Simon loses his Mark of Cain to the Angel Raziel in exchange for the sword "Glorious" to save Jace by separating him and Sebastian. Throughout the book, Simon and Isabelle's relationship progresses to the point where she trusts him enough to let him bite her when he is hungry. They spend nights together, much to Alec's horror. However, they still don't consider themselves dating for neither has confessed that they want to. Simon thinks he will just be dumped like the rest of Isabelle's boyfriends while Isabelle has trouble revealing her feelings and thinks Simon should make the first move. In City of Heavenly Fire, Simon admits his love to Isabelle. Throughout the book, Simon follows Clary and Jace—along with Isabelle and Alec—into the demon realm Edom to defeat Sebastian and find Magnus, Raphael, Luke and Jocelyn. In the demon realm, he saves Isabelle after she is bitten by a demon. Soon after, he tells Isabelle he loves her. As a result, they finally make their relationship official. At the end, after defeating Sebastian, they have no possible way of getting out. Magnus calls on his father, Asmodeus, who asks to help them