Aiding Valentine in his hunt for the Mortal Cup, Blackwell and Pangborn went to the home of Jocelyn Fray in New York. While Pangborn confronted her in battle, Blackwell went on to trash the apartment in search of the Cup, with a demon disguised as a dog in tow.
They then proceed to give the former Circle member Turned werewolf Luke Garroway a visit, drilling him about the Cup and taunting him into Turning, to no avail. During the interrogation, they were seen by Jace Wayland and Clary Fray. When Clary accidentally revealed herself while in hiding, Jace distracted them and engaged them in battle before the pair fled.
Days after their last visit, Pangborn, Blackwell, and Valentine raided the New York Institute. Ordered by Valentine to look for the other people in the Institute, he and Pangborn split up, with Blackwell opting to go to the upper levels of the Institute for his search. He ended up on the rooftop, where he found the mundane Simon Lewis and the Shadowhunter Isabelle Lightwood. He tried to take them down, but Hodge Starkweather fought and killed him.