The relationships that Cassie Blake has with various characters throughout the series.
- Main article: Cassie and Amelia
Amelia was the only family Cassie knew for the rest of her childhood years. Cassie and her mother were very close thought out the years. Their relationship came to an end when she got killed by Charles in a fire. She missed her mother even after her death. Her mother tried to protect her from learning about her magical heritage and her father. She evenually learn the truth about being a witch and read a letter that her mother left for her.Cassie and John
Cassie grew up without a father and knew nothing about him during her childhood. She heard about her father and the dark deeds he has done while learning about her dark magic and her other family. She finally met him though she wasn't too happy to see him due to his dark past and his absents from her life. She came to accept his help though still suspicious about him. She slowly grew close to her father through the time they share. She learned the truth about John's plan to have children to form a circle from Balcoin blood. She and Diana used the crystal skull to kill John.
- Main article: Cassie and Jane
After the death of her mother she move to Chance Harbor to stay with her grandmother who welcomed her with open arms. She grew close to her grandmother after she lost her mother. She trust her enough to reveal that she is a witch and ask her for guidance when the circle couldn't. Cassie would worry about her alot like when she went to see Herny and hasn't return. Jane kept Cassie and the circle's secret from the Elders. Cassie became saddened when Jane got killed and claimed the witch hunters were to blame.Cassie and Diana
Diana is Cassie's half-sister from her father side though neither of them were aware. She first met Diana at school and was the first one to befriend her. Her friendship with Diana got complicated through the connection she has with her boyfriend Adam. She would try to avoid a relationship with Adam because she didn't want to hurt Diana. They still remained friends even after Diana and Adam broke up. Cassie would stay with Diana at her house when her grandmother was out of town. In Crystal, Cassie figured out that she and Diana are sisters.
- Main article: Adam and Cassie
Adam was the boyfriend of her friend and half-sister Diana when they first met. They're written in the stars like her mother and his father were before them which is destiny and they shared a connection the moment they met. They would avoid being together so they wouldn't hurt Diana. They slowly grew close after he and Diana broke up. They finally kissed before Jake came down to see Cassie. She seem to deal with her feeling for Adam and Jake afterward. During Valentines day they start dating and they became a couple. They had a fight about their fathers and even apologize to one another after that. Adam told her that he loves her and they have sex for the first time. They drank an exilir to save Jake from the curse her father faked and they stopped being together. She still has feelings for Adam while he has none for her. She remembered due to her dark magic resisting the exilir's effects on her. She is saddened due to Adam not loving her.
- Main article: Jake and Cassie
Cassie first met Jake after Nick's death though she knew nothing about him. She grew friendly to Jake even when other especially Adam have doubts about him. She was able bring Jake into the circle. She grew more closer to Jake which made Adam and Faye jealous. While at Henry's house, they played truth or dare which Cassie is dared to kiss Jake which she did. They had second kiss which they stopped afterwards. She asked Jake to be her date for the fundraiser which he refused. Jake eventually accepted to be Cassie's date due to the feelings they have for one another. Jake begin to tell her about her father and the Balcoins. She learned that he is a witch hunter but was later saved by him in the end. He later return to help Cassie which she accepted his help even after what he had done. Their relationship grew apart and the two would remain friends. She was willing the drink the exilir to stop being with Adam to save Jake.
- Main article: Cassie and Faye
Their relationships is classified as enemies. Cassie first met Faye at school and she was the first to tell her she is a witch. She would often get tease and insulted by her from time to time. Faye would get jealous of Cassie due to their relationship with Jake. She would later accept that Jake has feelings for Cassie. Faye is also jealous of the dark magic Cassie has and did attempt to steal Cassie's magic but ended up with the circles magic. She felt cornered when she's blamed for nearly getting the circle killed instead of Cassie. Despite the problems they have for one another they still remain friends. They would often work together while in the circle.
- Main article: Cassie and Melissa
Melissa is the other person Cassie is friendiest with beside Diana. Melissa mostly hangs out with Faye and would tease Cassie a little with Faye. Though the two aren't very close they are fairly good friends. Cassie cares for her to the point where she goes looking for Melissa when the school was burning in Fire/Ice. They would often hang out with the girls without boys like help out with Halloween decorations or participate in Faye's anti Valentines day slumber party. The two seem to have respect for one another.
- Main article: Cassie and Nick
Nick was Cassie's nextdoor neightbor and the first member of the circle she met. Cassie can be annoyed by Nick by being looked through the window when she is changing. She and the circle were sad when NIck was killed drowing the demon. She seems to care for Nick when she looked at his window after his death. She would later pay her respect to Nick at the Boathouse. In Traitor, she and Diana were shocked to find out that the traitor witch is Nick who is alive.
- Main article: Cassie and Sally
Cassie became friends with Sally and she would help her out with the fair and the dance. She was worried about Sally after she nearly died from Faye's reckless push. Sally helped Cassie by getting her to dance with Adam. Cassie seems to stop hanging out with Sally after the dance. Their relationship afterwards is unknown.
- Main article: Cassie and Ethan
Cassie first met Ethan while at the Boathouse. He would tell her about how he and Amelia are written in the star and that its the same with her and Adam. He would try to help Cassie and Adam's relationship by talking to Adam, Cassie and Diana. She would try to get some answer about her father from him which he neglected to tell her. She became suspecious of Ethan about his connection to the witch hunters and the boatyard fire. Things took a turn for the worst when he stabbed John and Cassie nearly tried to kill Ethan. She avoided Ethan and the Boathouse after that.
- Main article: Cassie and Charles
Cassie first met Charles in Chance Harbor and learned that he is Diana's dad. She isn't aware that Charles is responsible for her mother's death and her grandmother's memory problem. He was kind enough to let her stay in his house with Diana until her grandmother is back. She thanked him for letting her stay in the house.
- Main article: Cassie and Dawn
She met Dawn who was the principal of the school she enrolled in as well as Faye's mother. She was very welcoming of Cassie after she lost her mother and asked if she need anything. Dawn was involved with Amelia's death with Charles and has an agenda with Cassie and the circle.
She first saw Eben in Jake's memories who killed the witches and tried to kill her father. She was captured by him and the witch hunters. Eben used Cassie against her father by spelling her to use her dark magic on John. The circle freed her from Eben's spell and she began to question about Eben's powers despite not being a witch. She learned about Eben's plan to summons demons and tried to stop him with the circle. She and the circle failed to stop him and he got away. Cassie and the circle are preparing themselve to up against Eben with crystals.
She first met Isaac along with the circle after they were kidnapped. She was kidnapped by him again to be taken to the council of witch hunters. She threaten him if he didn't let Adam go. While trying to get information from Isaac nknown to her that Isaac was killed by Eben. She was against having a truce with the witch hunters who are loyal to Isaac due to the claim that they killed her grandmother.
- Main article: Cassie and Luke
Adam introduce Luke to Cassie and she became his date to the dance. Faye invited him to Cassie's halloween party. He kidnapped Cassie and revealed himself to be a witch hunter. He was killed by Cassie using dark magic to burn him alive.
- Main article: Cassie and Kate
Cassie met Diana's grandmother Kate while at her house. They talked about her grandmother and the loss of Henry Chamberlain. Kate revealed that Cassie has dark magic and would talk about her father. Kate offered to help get ridded of Cassie's dark magic. Kate tried to kill Cassie while buried, but Cassie's own magic over came hers.
Main article: Cassie and Zachary