Crowley first meets Ferid in the 13th century when Crowley looks in on a case of serial murders. He finds Ferid to be charming and highly intelligent despite his flagrantly perverse nature. Ferid convinces Crowley to become his partner in tracking down this serial murderer after one of Crowley's former comrades is murdered. He eventually kills all of Crowley's friends. When Crowley gets turned into a vampire, Crowley says that Ferid was most likely laughing while he watched.
By the time in the 21st century, Ferid says he does not care whether Crowley dies or not but later goes on to consider Crowley his dear friend and lackey. Crowley appears completely at ease with Ferid's whims. Crowley follows and supports Ferid's faction because according to him Ferid makes interesting things happen. Crowley suspects Ferid may be the one sharing information with the humans, but he complies with Ferid's demands even before questioning the motives. They work together to dethrone and imprison Krul Tepes.