Clary infiltrates his inner circle through Jace and they both continually mistrust each other but are forced to work together when they are attacked by enemy demons. Eventually Clary learns the truth of his plans and they engage in a bloody battle. Unable to kill him because it will kill Jace too, she gives up but successfully destroys their base of operations with one of her runes. After a dark ritual, he uses the Infernal Cup to create more Dark Shadowhunters and almost turns Clary but is quickly stopped by the arrival of the Lightwoods and their allies. Before he manages to escape, Clary is forced to stab Jace with the angelic sword Glorious, severing his bond with Sebastian and causing the latter horrible pain. At the end of the book he sends a message to Maryse Lightwood: severed angel wings with a single,piece of paper saying ´´I am coming.´´ In City of Heavenly Fire, Sebastian is attacking institutes around the world and turning Shadowhunters into Endarkened. He then goes and attacks the Citadel, and kills many Shadowhunters but is forced to flee when Jace loses control of his Heavenly Fire. Sebastian then later visits Clary and tries to convince her to leave with him, offering her mercy but she refuses. Once again Jace and Sebastian fight but Sebastian proves that he cannot be hurt by anything other than the Heavenly Fire after he stabs himself and then leaves unharmed. Sebastian offers to leave all of the Shadowhunters in Alicante alone, and return Jocelyn, Luke, Magnus, Raphael and Meliorn, whom he has kidnapped, if the Clave turn over Clary and Jace to him. Clary, Jace, Simon, Alec and Isabelle all travel by portal to the Seelie court and travel through to Edom, where Sebastian is hiding. Sebastian is well aware of this and plans for them. When they arrive Sebastian defeats them all and forces Clary by his side. When he is unaware, Clary stabs him with a sword that contains the Heavenly Fire, burning away all of the demon blood in him. He dies surrounded by Clary, Jocelyn and Jace. Clary mourns for the brother that she could have had. Clary later spreads Sebastian's ashes over Lake Lyn. Physical appearance He is said to be the spitting image of Valentine. He has naturally white/silver hair, is very buff, and has deep black eyes. He dyes his hair black in