in the mortal instruments are clary and jace related
List of The Mortal Instruments characters At last, Magnus wakes Clary's mother Jocelyn, who informs Clary that Jace is not her brother. In fact, Sebastian (the real Jonathan Morgenstern) is her brother. It is soon revealed that Sebastian is a spy for Valentine and that he tried to seduce Clary into teaming up with him. Clary then tries to locate Jace to help him. She runs into Valentine, who ties her down in order to complete his summoning of the Angel by using her blood. Then, when Jace arrives to rescue her, Valentine forces her to watch as he fatally stabs Jace in the chest. Upon summoning the angel, Clary changes the marks on Valentine's summoning circle, giving her the ability to control the Angel, and after Valentine is slain, she wishes to have Jace back. After Jace is brought back to life, the two get together, now that they know that their love for each other isn't incestuous.
City of Glass (Clare novel) After a few days, they have a funeral for the people who were killed in the attack. Later that day, Simon meets up with Isabelle to comfort her as Jace walks Clary back to Amatis's place. Later that night, Jace comes to Clary’s place and sleeps with her and in the morning leaves a note. When Clary gets downstairs to save Jace from his mistake, she meets her mother, which she reacts with anger. Later, her mother tells her the truth: Jace was raised by Valentine, but is not his biological son, but rather Sebastian is, and by extension Clary's brother. Clary runs to the Accord Hall to work out a plan to make both Shadowhunters and Downworlders fight together, and during the decision process, Jocelyn, Clary’s mom, releases the truth, and in the end, the Clave decides that both can work together to fight the battle. This allows Clary to use her rune abilities to create a bond that allows them to fight together. While Jace is in a battle with Sebastian, he discovers Valentine raised the Angel Raziel, which was raised when the Mortal Sword stabbed into Jace's heart. The angel rose, but the angel killed Valentine and granted Clary’s wish to bring Jace back. The story ends with the confession of love between Jocelyn and Luke.[3]