Alternate Ending of City of Heavenly Fire. Contains spoilers.

Part 1

Jace's eyes moved around the room, and Clary followed his gaze. The light outside the windows had dimmed slightly, and she could see the dais more clearly. On it sat two immense- well, the only word for them was "thrones." They were ivory and gold, with gold steps leading up to them. Each had a curved back embossed with a single key. 

"'I am he that liveth, and was dead,'" said Sebastian, "'and behold, I am alive for evermore, and have the keys of hell and of death.'" He made a sweeping gesture toward the two chairs, and Clary realized with a sudden jolt that there was someone kneeling beside the left-most chair- a Dark Shadowhunter in red gear. A woman on her knees, her hands clasped in front of her. "These are the keys, made over in the shapes of thrones and given to me by the demons who rule this world, Lilith and Asmodeus. Amatis, go and fetch my dear mother."

Amatis left the room and Sebastian's dark eyes moved to Clary, and she felt gaze like cold fingers walking up her spine. "I don't know why you're showing me this," she said. "What do you expect? Admiration? You won't get it. You can threaten me if you want; you know I don't care. You can't threaten Jace- he has the fire of Heaven in his veins; you can't hurt him."

"Can't I?" he said. "Well, I suppose I won't even have to."

Jace stepped forward with an inarticulate growl- and stopped in his tracks, several feet from Sebastian. He put his hands out, but they seemed to collide with something translucent, an invisible wall. 

Sebastian snorted. "As if I'd let you get near me- you, with that fire burning in you. Once was enough, thank you."

"So you know I can kill you," Jace said, facing him, and Clary couldn't help but think how alike they were and how different- like ice and fire, Sebastian all white and black, and Jace burning up with red and gold. "You can't hide in there forever. You'll starve."

Sebastian was about to click his fingers, when the door to the room opened and Amatis strode in. She was followed by a large group of Endarkened warriors. Their faces were blank as they silently ranged themselves along the walls of the room, but Amatis looked worried. "Lord Sebastian," she said. "Your mother is not in her cell." 

Sebastian frowned and tightened his bleeding hand into a fist. All around him the runes were burning fiercely now, with a cold ice-blue flame. "The others must have let her out," he said. 

Clary felt a surge of hope mixed with terror; she forced herself to remain silent, but saw Amatis's eyes flick toward her. Her lips curved into a smirk. "Would you like me to set the rest of the army to searching for them?" she said to Sebastian. 

"There's no need." He looked at Clary, and then Jace, and smiled. "I will bring them to me."