Haruka idolizes him because his song, Nanairo no Compass, saved her and motivated her to become a composer. Although at the start of the series, it was told that Hayato was Ichinose Tokiya's twin brother, it is later revealed that they are one and the same person and Haruka was the first to know.
They meet at the day of the entrance exams, and from there on out, Otoya has been very kind to Haruka. They were paired up to create a song, and together they achieved one of the highest scores. He is also one of the six guys who requests her as their partner for the graduation audition. Later on he is grouped with the other five into a new group called ST☆RISH. Haruka was not able to choose between them, afraid that she would be crushing the dreams of five others. It has been revealed that he has had a crush on her for quite some time, which is shown in the anime. In the second season Otoya expresses his happiness at being able to live in the same place as Haruka but is soon reminded that he can't have a romantic relationship with her.
During Episode 5 of the second season he is seen to be overjoyed at being in the haunted house with Haruka and blushes when she gets scared and holds his hand. In the same episode he nearly confesses his love for Haruka but they both get scared by Cecil's paper ghost, which dropped from the ceiling. What he was about to say was forgotten by Haruka.
Masato is first introduced at the start of class but it is later revealed that he has actually seen Haruka before, singing with a group of children in a playground. Seeing her sing so happily inspired him to pursue a career as an idol. After Haruka freezes up in front of the class, Masato spends time with her after school to help her get over her fear. He is one of the six to request her as his partner for the graduation auditions, though he sent his request via a letter in her locker.
In the second season Masato is cleaning Haruka's room when she comes in. After saying they greet each other, Masato realises how he has been having some strange feelings towards Haruka and wishes to stop them.
Masato gets an offer to act in a historical play in which a samurai kills the greedy and selfish people and punishes them. While doing so his love interest is worried about him and claims she loves him. However, he can't return her feelings because he doesn't know how to. There is then a scene where the samurai and the love interest embrace. He accepts the role to help achieve the Uta☆Pri Award.
All the boys of ST☆RISH realise Masato's struggle and decide to help him by acting out the play. Tokiya dresses up as the love interest. Masato acts perfectly and is praised by the boys, until he reaches the embracing scene and can't do it. In the morning, Masato leaves to go visit he grandfather's grave, where his passion and inspiration for the performing arts is revealed. Masato experiences a flashback of his grandfather who tells him that if you're working with the people who support you, you'll always succeed. When he goes back to try and act out the play one more time he fails yet again to get the embracing scene right.
Cecil tells him imagine that it's the girl he loves the most. Masato imagines Tokiya as Haruka saying the lines, "I always love you." Embarrassed, Masato claims he can't and goes out for a walk. Cecil tails after him and asks why he became an idol, to which Masato replied that he was inspired by the girl he loves the most. He then thinks back to Haruka singing "Twinkle, Twinkle Little Star" with children at a playground. At the audition, Masato performs amazingly, gets the role, and is finally able to do the scene.
Back at the mansion, Masato is by a tree watching the sunset. Haruka finds him and congratulates him on getting the role. Masato says he sang the song she composed for him and if it wasn't for her, he wouldn't have passed. Upon leaving, Cecil comes down from the tree, having witnessed everything and tells Masato the girl he love the most is Haruka, but that can't have her due to the rule that forbids idols from falling in love. Masato says he doesn't care about the rule because he's all ready bound to her by music.
Haruka seems to be on friendly terms with Natsuki who likes her since she is cute and very hard working. She also once said that she loves basking in the sun just like Natsuki's dog, Elizabeth, which made Natsuki feel happy about what she said that day. In the second season, Natsuki finds himself really happy about being able to live near Haruka.
During the Saotome Academy days, Haruka is happy because she finally gets to go to the concert of her favourite idol, HAYATO. All of the others make offers to accompany her, but she denies their requests and assures them that she'll be fine. While in the city she gets lost. While looking for help, she sees a man resembling Natsuki (except he was not wearing glasses) writing music. She asks him for help, but receives a death glare to her dismay. He then tells Haruka to go away because she is annoying him. Meanwhile, two boys who are talking to each other walk by and one of the boy accidentally tosses rubbish that lands on Natsuki's head. Enraged, Natsuki corners the boy, punches the wall behind him so hard it leaves a mark, and stuffs the trash in the boy's month. Syo then comes along and immediately places glasses on Natsuki's face.
After Natsuki was turned back back to his normal self, they head to a cafe. While sitting in a cafe Syo tells Haruka that Natsuki has a split personality called "Gemini syndrome" and that his other personality goes by the name Satsuki. Satsuki has increased strength and is considered to be the darker side of Natsuki. His Satsuki personality manifests itself whenever Natsuki's glasses are removed. Satsuki acts as a body guard for Natsuki and protects him. The only way to get Natsuki back is to put glasses (of any sort) on him. Once Natsuki puts on glasses on again, Natsuki will have no memory of being Satsuki, or what his other half has done. Syo tells Haruka he doesn't know what triggered Natsuki to create Satsuki.
At the concert, HAYATO performs but while turning around, his microphone falls out of his hand, abruptly stopping the performance. Natsuki's glasses get knocked off by a spectator, and the weather becomes dark and rainy. Natsuki transforms into Satsuki and becomes ballistic due to screaming girls running away from the weather and screams in anger. Satsuki starts running towards the stage. Syo tells Haruka to get his glasses that have fallen off and are now broken because someone stepped on them. Haruka takes the glasses from Syo and runs towards the stage.
Satsuki fiercely knocks out the bodyguards and tells HAYATO to give him the microphone, the latter believing the former to be Natsuki when he does. Satsuki then sings really well albeit with a darker tone and the camera crew continues to film him. Ren, Masato, and Tomochika are all watching Satsuki and feel that something about Natsuki is different but enjoy the song anyways. Haruka reaches up to Satsuki to place the glasses on him but he grabs her by the arm and brings her close before she can. Satsuki whispers in her ear, "Let's have fun." Satsuki asks her, "Aren't you afraid?" To which she replies, "No, because I know Natsuki would never do anything to hurt me." Satsuki becomes stunned by her words. Suddenly Syo sneaks up from behind and puts the PRIPRI mask with glasses that Natsuki was wearing during the concert on Satsuki. Satsuki stops whats he's doing and turns back to Natsuki who has no memory of what happened.
The first time Haruka and Tokiya meet, Haruka believes that Tokiya is actually HAYATO. However, her belief is later crushed when she is told that Tokiya is not HAYATO, but is actually his younger twin brother.
Tokiya has paid a lot of attention to Haruka ever since they first met. Tokiya would often question on many occasions over how Haruka could always try her best. After Haruka discovers his true identity, Tokiya distances himself from her. However, his heart is softened by Haruka's kindness when she states that she wants to hear his songs. Surprised, Tokiya finally realizes that he can start over again and says that he will try singing. Ever since then, he has been seeing Haruka in a different light, and has began to develop feelings for her.
Ren and Haruka met at the day of the entrance exams and Ren has been very kind to her ever since. One day, he happens to see Haruka help a lost little girl find her mother and so decides to gives her the nickname "Little Lamb". Like with most of the other girls, Ren treats Haruka kindly and thinks that she is nice because she helped him once. In the second season, Ren expresses how happy he is that they are able to work together again by dozens of rose bouquets he grew, all of which he named after her. Haruka then makes a song for Ren and explains that his songs warm up her heart. He thanks her and smoothly claims he'll only sing it for her ears only.
During Ren's modelling concert, a sudden power cut throws the whole arena into darkness. Ren then decides to calm the crowd down by singing the song Haruka made for him. Haruka feels touched and upon realising it's her song, and decides to play the CD with the music of the song she composed. However, when she reaches the entrance she is denied entry. Fortunately, she runs into Ren's older brother, whose company is sponsoring the modelling concert. He accepts CD from her, determined to help his brother.
Combined with Haruka's song now playing, Ren's singing "warms up the audience's hearts" and the concert ends on a successful note. Outside the concert hall, Ren thanks Haruka and tells her how he wouldn't have made it if it wasn't for her. He goes for a kiss, but Haruka, feeling uncomfortable and not ready for it, closes her eyes. Ren then whispers, "It's okay, I'll wait until your adult," ending the conversation. He then goes to talk to his brother, who sprained his arm trying to get the CD to the recording station. He claimed he did so for Ren and not for the company. He also explained that he enrolled Ren into Saotome Academy because of his talent for singing that warms up people's hearts and mesmerizes them.
Syo sees Haruka as a friend in the beginning because of she encourages him to look up to Hyuga Ryuya. Once he realizes that she understands his admiration, he begins developing romantic feelings for her. Like the others, Syo also requests to have Haruka as his graduation partner. In the second season, it appears that he and Haruka have been very friendly since Syo seems to have lent her one of his favorite movies. When she tells him that next time she will give it back to him, he lets her keep it as a present. In Episode 3 of the second series, Syo also thanks Haruka for helping him with his audition after he saves her from falling. After he saves her, he holds her as she cries from fear, and says that if anything had happened to her he wouldn't know what to do. He then gives her his favourite hat, showing how much he trusts her. Upon giving her this hat, he tells her that he will start up a fan club for himself. Haruka tells him that she will join and that makes Syo feel really happy.
Cecil is a prince of Agnapolis who was cursed and turned into a black cat. In the anime, he is the cat that Nanami Haruka names Kuppuru (meaning black and fluffy) and takes care of. Haruka cares for Cecil because he was the cat that she took care of, and they are usually seen together when Haruka is alone or depressed.
In the second season, he tells her that her songs saved him and he confesses his love for her, much to the other boys' dismay. However, since romantic relations aren't allowed between idols, he tells her that he'll always be by her side and that he desires to only sing the songs she writes for him. Cecil asks the boys of ST☆RISH why they became idols, suggesting that Cecil himself wants to be an idol despite the fact that when asked, Cecil denies he wants to be an idol and just wants to sing Haruka's songs with his poetry. When Cecil asks Haruka why she loves ST☆RISH so much, Haruka replies that they all sparkle, and that it makes her want to watch them forever. This encourages Cecil to do his best and study together with his senior Camus.
In the second season, Cecil says he says to Haruka that he's sorry he couldn't be her prince, and that he now wants to become an idol because he wants to make her and all kinds of people smile. He began to feel this way because he guest starred in a reality comedy show with Otoya, where he was able to make many people smile. Haruka tells him that she will support him all the way and that he would make a great idol.
The other members of ST☆RISH say that they'd tease him but are also okay with him wanting to become an idol. While singing Hoshi no Fantasia, Haruka asks Cecil to join ST☆RISH, says that Cecil was what was missing from her song and that she would like to write a song for all 7 of the boys. Cecil then becomes an official member of ST☆RISH.