Yukimura Ryuu - Ryuu is Aiko's older brother who attends Yusei High School. He was studying abroad in America before Ichiro arrived. When he was younger Ryuu always took care of his sister, also being the overprotective type, but he began to spend less time with her and eventually left to America. Aiko admires her brother but misses him a lot when he is not home.
Yukimura Akemi and Yukimura Rei - Aiko's parents own a hospital and work 24/7 as doctors. Despite being constantly alone without her parents and older brother, Aiko tries to stay strong and let her parents continue with work.
Kage Ichiro - When Aiko was walking to school she witnesses Ichiro standing on top of a light post, and makes a remark about his red eyes, before he disappears. She encounters him again after he saves her from a Kurayami. At first she doesn't know he is a prince, not until Frore explains to her. She then offers him to live at her house while on earth, despite learning about his past, she decides to trust him without any second thoughts. The two have become close friends since the first episode, as Aiko seems to be more opening to him and the two are often seen together. She is very kind towards Ichiro dispute his initially cold attitude and comes to understand the hardships he's been through. Thus wishing he would smile more. They are both well known throughout the school which surprises Aiko. Nevertheless she respects his abilities and values his friendship dearly. Both Ichiro and Aiko usually call each other by their first name.
Mitsue Sayuri - Sayuri has been Aiko's childhood friend since elementary. They met during the time Sayuri was being bullied for her terrible tasting cakes. When Aiko saw this she defended her, despite being scared herself, and said that her cake was delicious, encouraging her to do her best. Sayuri's loyalties to Aiko run deep as a result of this fateful encounter. Aiko appreciates Sayuri's protectiveness and sees her as a very important friend, one of the few people she hangs out with. Aiko is also concerned with Sayuri's dislike of Ichiro. She is the one who gave Aiko the nickname "Ai-chan".
Frore - Frore is a wolf-like fairy mascot and Aiko's transformation partner. Frore and Aiko have a very close relationship, both showing great care and concern for each other. Aiko is extremely kind and caring towards him and always watches out for his safety and tries to keep him unharmed. She tends to address him as "Ototo" which means "little brother" because she thinks of him as a little brother she never had. It is hinted that he may have a small crush on her.
Kawasaki Aoi - Aiko first meets Aoi when she and Ichiro (are somewhat forced to) volunteer to help the student council. She found Aoi to be very intelligent and beautiful and wanted to get to know her better. The two enjoy each other's company and managed to become fast friends despite Aoi being the total opposite of her. The two are positive influences on each other and Aiko continues to inspire Aoi with her innocence. She respects Aoi and thinks of her as a big sister-like role model and responsible senpai. She was thus extremely happy when Aoi became a Cure.
Akanishi Ren - Aiko admires Ren and in return Ren is enamored of Aiko. They become quick friends. Ren seems to genuinely care for Aiko's well-being and loves to dote on her. She is the first person to notice Aiko state of well being but decides to keep it to herself, knowing that Ichiro would be able to change her. She enjoys teasing Aiko of her relationship with Ichiro; which Aiko is oblivious about. Aiko is also a fan of Ren's families boutique, Star Jewelry, and is often tricked into being the model for her clothes and designs.
Matsushima Tomiko - Aiko is considered to be Tomiko's rival, although this is ultimately one-sided. Tomiko is madly in love with Ichiro, therefore she is jealous of Aiko whom is the closest to him. However, Aiko is completely blind to this and treats Tomiko with kindness. They do both get along rather well, especially when they both agreed that love was important for what you want in life. Aiko later finds out about Tomiko's feelings for Ichiro and says that she's cute.
Matsushima Taro - Aiko appears to be on good terms with Taro, respecting Taro for his serious attitude and very enthusiastic encouragement; Taro appears to also respect and treat Aiko as his idol, being the president of her fan club. They are first seen interacting each other when Taro greets Aiko with a swarm of students.
To be added.