Jonathan Morgenstern: You want me to be your weapon.
Seelie Queen: I want you to be my king. Together, we will destroy the Shadowhunters and rule the earthly realm side by side.
Jonathan Morgenstern: I prefer to rule alone.
(Seelie Queen turns into the child version of herself...)
Seelie Queen: Please, Jonathan. Please. You wouldn't dare hurt a child. Have mercy.
Jonathan Morgenstern: Mercy is for humans. And I'm no longer human.
Jonathan Morgenstern (to Clary): The first time I ever heard your name. Clarissa Morgenstern. It was like music to my ears. I felt something that I had never felt before. Hope. That moment changed everything for me. I realized that you were the only person that I needed. I felt it. Finally, I had someone to fight by my side. Not against me, not in spite of me, but with me. Everything I do, I do for you. I want the Morning Star sword for you. For us.
Clary Fairchild: Jonathan, if you're looking for pity, you're wasting your breath.
Jonathan Morgenstern: I'm not interested in pity. Just understanding. I can't deny the things I've done. But you need to know that's behind me now. I can change. I want to change. Because... whatever good exists inside of you, at least some of that has got to be inside of me too. Somewhere. I intend to prove that to you.
Sebastian Morgenstern: I'm a dead weight, am I? I know when I'm being played.
Valentine Morgenstern: Believe me. Where I need to go, it's too dangerous for you to follow. You, Jonathan Morgenstern, are brilliant... and as cunning and vicious as I have ever hoped for. Listen to me. I will come back for you. I promise.
Clary Fray: I understand he has demon blood, I know what he's capable of, but... but he's my brother. God, that's stupid, right?
Sebastian Morgenstern: Oh, no. No! God, it's not stupid at all!
Clary Fray: And if there's any humanity left in him, shouldn't we at least try to save him?
Sebastian Morgenstern: I think so.
Sebastian Morgenstern: Jace is trying to sabotage me. He's trying to... make Clary hate me. But I swear to you, I will end him before I let that happen.
Valentine Morgenstern: Listen. Once we have the mirror, none of this will matter.
Sebastian Morgenstern: I can't have Clary hate me. Not after everything I've been through.
Valentine Morgenstern: Clary doesn't care about you.
Sebastian Morgenstern: Yes, she does.
Valentine Morgenstern: No, Jonathan. She only cares about an English Shadowhunter named Sebastian Verlac. When she realizes the truth about you she will only despise you.
Sebastian Morgenstern: No. You are the one that she despises. I am her brother! She loves me.