Kadir Safar is a Shadowhunter, said to be the second most important person in the New York Conclave next to the head, Maryse Lightwood. Being an important asset to the Conclave, Maryse relied on him often.
Some time after the culprit behind the deaths of several Shadowhunters, particularly former Circle members, was revealed, Kadir helped organize the capture of Camille Belcourt. When Alec Lightwood and the others got into trouble with Camille and Lilith, he sent a fire message asking the Conclave for backup, and Kadir was among those who responded. He and Maryse were the ones who went to the roof to check on Jace and Sebastian and found them missing.