Kirihara Atom (桐原アトム, Atom Kirihara) is the Main Character of the Series. He is the Club President and a member of Marginal #4 under Pythagoras Production. He is voiced by Masuda Toshiki (俊樹, Toshiki Masuda)
Atom has Short maroon color hair that turns pale red at the edge, with three stars pin on his hair. He has dark brown eyes as well.
For his school uniform, He wears a white button up shirt with a pink unzipped jacket, That is covered with a dark grey and black School blazer, that is pushed up to his elbow. On his right wrist, He wears a black and red watch and on his left wrist he wears a black sweatband. He wears grey pants, with his right pushed up a bit with red and white shoes.
His official Debut Outfit is a short, sleeved collar white button up shirt that is covered by a half red jacket, with black shoulder pads with gold attached to it. He wears tight black pants with three gold string slanted to the side. He wears the outfit with a black tie and black boots with golden strings, and black finger-less gloves.
His opening outfit is a white shirt that is covered by a pink button up coat with grey, white and pink rolled up sleeved. He wears black pants with a white long sleeved tied around his waist with red and white shoes.
His practice clothes is a white and maroon color t-shirt with black sweats and white shoes. He isn't with his pins.
His normal wear is a long black sleeved that's pushed up with a white T-shirt over it, with a tie dye of red and orange on left shoulder. He wears black sweats with a orange scarf around his waist.
Atom is a very energetic, normal High School student who seems to to have way more energy than most. He is very passionate about his career as an Idol and want to go far with Margi. Marginal #4 is very important to Atom and his dreams with Margi, Is to make it to the Shooting Star Hall for their own solo concert. He is very dedicated to his fans and always tries to be the most followed on Skitter. Aside from being Energetic, He is very childish and loud. But, If need to, Can be very serious. Which stills, Sometimes shocks L.
Unlike the others, He wasn't scouted. He went to Audition. His father wanted to become a Idol, So Atom made it his goal to follow in his footsteps.
In the beginning, He didn't like the idea of being in a unit and wanted to be solo. But, He saw how determine R was for them all to become a group, and it changed his mind.
- Nomura R: He was the first to become friends with the twins. His has different view of both twins. He sees R as a very close friend and a very kind person. He sometimes says that he is too kind hearted. He, along with L, and Rui suggested that R become the leader because he brought them together.
- Nomura L: He sees L as a close friend as well, but a huge pervert. The two are both aware that the girls flaw over the group appearance and sometimes uses it to their advantage. He will sometimes say that he as well is kind-hearted, But not as much as R. He is more relax, but is a bit weird.
- Aibu Rui: He was a new member to Marginal #4 after Rui left his group and was place with them. At first, The two butted heads a lot and still do, Sometimes. They are the complete opposite. Rui is Quiet and straightforward, While Atom was loud and cheerful. But, Over time, The two became close friends, and Atom even considers Rui as a 'Brother.'
- Makishima Shy - Atom's Senpai
- Himuro Kira - Atom's Senpai. Kira tries the hardest to bring Atom and Tsubasa together as friends. But, Atom has great respect for him.
- Takimaru Alto - Atom's Kouhai.
- Shindo Tsubasa: The two butts head a lot as they are very much alike in their personality; They are both stubborn, loud, and don't take no as an answer. But, They both have deep respect for each other and their dream. They are both rivals in Skitter and as an Idol.
- Nakama Teruma: Atom often gives Teruma advice on what to do in his group and what not, Just like Shy and Kira did to him. On Episode 6, The two were involved in a love scandal, When they thought he was out with a girl, But it was really Teruma.
- "The name's Kirihara Atom. I'm Marginal #4's Wild Shooting Star!" - Episode One
- "Of course, Just singing it is easy. But I want it to really come from the heart. Otherwise, I can't put my soul into it." Episode Two
- "You two sure get along well." - Episode Three
- "I mean, Rui did transfer in and all, But when it comes to school stuff, He's always holding back. But, I personally want him to have fun, You know?" - Episode Four
- "Yeah! It'll be the four of us together forever!" - Episode Five
- "Yeah! I was just being a model senpai and coaching him on being prepared for the debut." Episode Six
- "Well, In our case, Our hearts became one with the starclusters', and that's how we filled the sky with stars!" Episode Six
- "That indeed would result in despair, But I don't think I'd mind using a textbook that smelled like barbecue sauce...So it wouldn't be the depths. More like the bottom of a kiddie pool." - Episode Seven
- "It was my dad's dream to become an Idol, So I was steeped in that dream ever since I was a small kid." -Episode Nine
- "Let me just say this. We'll be the unit that puts the most stars into the sky at Shooting Star Hall." - Episode Ten
- "Well, I guess it's something that relates to our dream." - Episode Eleven
- "I'm Sorry. This wouldn't have happened if I hadn't said anything about trying to put our kisses into a rocket in space." Episode Twelve
- Favorite Food is Korean BBQ
- Important thing is being on stage
- He's obsessed with how many followers he has on Skitter
- Best Subject is Physical Education
- His personality on the game is a bit different than on the Anime. On the Game is is Hot-blooded, Selfish and thinks the groups revolves around him. But on the Anime, He's more relaxed, Louder and Childish.
- He has a Ore-sama personality.