"Then I declare you bonded for life," Harry answered, his grip on the blade tightening. And as the blade drew blood from his hand, the blood on both of them erupted into red sparks—sparks that flew together, intertwining in an intricate pattern, swirling and multiplying, and Harry gasped as the dark magic flowed through him, washing away the ache that had never really left him since Voldemort’s first curse.