Grace's Heirloom Bracelet

Grace's heirloom bracelet, which reads 'Loyalty binds me,' is a symbol of her manipulative personality. When she forcibly clamps it onto James' wrist at the end of the book and previously when she convinced him to wear it of his own accord, Grace demonstrates her desire to have a strong hold on James' whereabouts, his mind, and his heart. She wishes to control him not only physically -- as the bracelet clearly has some powers of control over James' feelings and actions -- but she also wishes to emotionally manipulate him time and again. The bracelet is a symbol of James' servitude to her.

Matthew's Flask

Matthew's flask is very evidently a symbol of his alcoholism, and more implicitly a symbol of his mental weakness. Though he tries to be a strong Shadowhunter and a reliable friend, he often fails in both endeavors...