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.
One of Crowley's servants. Immature, playful, and jealous character. It is unsure how Crowley exactly feels about her and Horn, though he did warn them to be careful with the cursed weapons as wounds from them do not heal. He attacked her with a cursed sword to test its ability, shocking her. Faithful to lord Crowley, both she and Horn seem to have a desire for his blood.
Crowley knows of Mikaela and his position and story. He attacks Mikaela and Yūichirō's group in a local fishing village to hold them up until Ferid arrives.
Currently a city guard working with Mikaela Hyakuya and Lacus Welt. Ferid gives orders to him on the Shinjuku battlefield.
One of Crowley's servants and the one he most often converses with strategically. Which might be because she is the mature and serious of the two. She can usually be found with Crowley along with Chess. Both she and Chess seem to have a desire for his blood. It's unsure how Crowley exactly feels about her and Chess, though he did warn them to be careful with the cursed weapons.
Crowley seems wary of her power and considered her a possible candidate to be leaking information to the humans. He acted as a distraction for Ferid attacking her to catch Krul off guard and defeat her, though he seemed to have some doubts about the whole plan.
Saito is Crowley's sire, however it is unknown if Saito is aware of this. Ferid talks of killing Saito with Crowley however Crowley knows they are too weak to kill their father. Crowley has dubbed Saito to be a monster after seeing him for the first time.
Crowley fights her squad when they enter Shinjuku. He pinned her down and drinks some of her blood. They are currently travelling together and at Ferid's mansion to tame Yuu's Seraph. She's still wary of Crowley being with them but sees the benefit of having a strong fighter like him amongst their group as long as he's on the same side.
Crowley fought Shinoa's squad when they arrived in Shinjuku, and Yūichirō managed to cut off Crowley's arm. He considers Yūichirō to be quite strong for a human. Crowley takes interest in fighting the boy again for another time after Yūichirō displayed his powers after taking more than one pill and thus making his demon side come out, Crowley was clearly excited. Apologizing softly to Ferid that next time, he might "just drink this one dry." He later attacks Yūichirō and the group at a little fishing village in order to stall them. Later he is much kinder to Yu and the rest of his squad, helping him rescue Ferid and letting them into Ferid's mansion. Unlike his comrades Yu seems to have accepted Crowley as one of his comrades, the two banter in an almost friendly matter. In return, Crowley looked almost regretful upon learning that he will have to show to Yu the corpses of his adopted family, a first sign of compassion he ever showed.
The leader of the human resistance in Shinjuku and the one in command of the attack against the vampires in Nagoya. Initially, Guren wanted to avoid targeting Crowley, but added him after finding out the vampire killed an amount of 10/30 soldiers and was holding the remaining 20 captive at his stronghold. They face off with Shinya aiding Guren but the two of them are quickly overpowered. Crowley, having decided beforehand to capture one of the commanders for information to present to Ferid, allows Shinya and the other soldiers to retreat while he takes only Guren as captive. He is surprised to hear Guren is a namanari, not thinking a human like him could have been pulling the strings at all.
Crowley shortly encounters Kimizuki during the battle in Shinjuku. Horn drinks his blood when they are defeated. Kimizuki has dubbed Crowley the "red haired monster". Crowley has currently been 'accepted' into their group but Kimizuki doesn't really trust him yet.
Guren launched an attack on Nagoya, and when his forces reached the city hall, Yoichi was tasked with sniping Crowley. As soon as Yoichi fired the Gekkōin at him, Crowley catches it's manifestation and flings it aside. Yoichi recognizes Crowley as the vampire noble his squad rammed a jeep into on their way from Harajuku to Shinjuku during the previous vampire attack. Later he once again is the one to recognize Crowley when they near their hiding place at a local fishing village, warning the others.