Erika Sakura is the main character of the manga "Kusumi-kun, Kuuki Yometemasu ka ?" and the most popular girl in her high school. She is in the same class as Yukko and Juri, her best friends, and Kuzumi since they are in high school.
On the contrary to Kuzumi, Erika is a noisy person, she speaks very much and loudly. She is very expressive, narcissistic and she has average intelligence. Erika is a curious girl. She doesn't say what she really thinks ; she often says that she thinks of Kuzumi as a plain, dull and boring guy and that she can't be in love with a guy like him but this is wrong because she's in love with him, thinks he is cute and gentle.
Erika is a girl who is quite small, but taller than Kuzumi. She wears her brown hair as pigtails and has brown eyes.
Yukko and Erika know each other since middle school. They passed the entrance exam for their high school together. Yukko was happy and told Erika she will be able to tease her for three more years.
Since Yukko noticed Erika's love for Kuzumi, she can't stop teasing her about that and ever took pictures of her sleeping with Kuzumi at night during school trip.
Erika met Juri when they passed the entrance exam for their high school. Erika saw Juri yelling she passed the exam. At that moment, Erika did not talk to her but she thought that Juri was quite an energetic girl and that it would be great if she was accepted.
Erika is interested in Kuzumi because of his mysteriousness. She started to stalk him at school to know more about him. Step by step, she falls in love with Kuzumi, without even being officially friends with him and while continuing to think this boy is weird, plain and boring. But, as the most popular female student in her high school, she can't accept being in love with the one who is unpopular and she can't help but to compare Kuzumi to other boys she thinks better than him. Moreover, according to Erika, Kuzumi is dense. He can't read the atmosphere, this is why he never noticed the feelings she has for him until she confessed. Plus, Erika sees Kuzumi as a kid, because of his appearance, his love for birds and the way he likes to play games at the summer festival. When Kuzumi smiles, Erika thinks he has the cutest smile she's ever seen.
Kuzumi and Erika often run into each other by chance, outside of high school. They have seen the fireworks for the summer festival together because Erika wanted to hide herself from some guys who were trying to flirt with her and she finally found Kuzumi watching fireworks alone. When Erika went to the cinema to watch a romance's movie, she saw Kuzumi. And unexpectedly, Kuzumi sat next to her to watch the same movie and even fell asleep on her shoulder during the movie. Erika also went at Kuzumi's house to give him some documents he needed but met his dad instead and was dragged inside by the latter. Kuzumi's dad spoke with Erika before Kuzumi returned back. Kuzumi seemed shocked when he saw Erika in his house with his father and was quite mad at this one for teasing both him and Erika.
Erika uses a picture of Kuzumi, while he was sleeping, as a wallpaper.
When Erika went to cinema to watch a romance movie, she saw Kuzumi. She planned to come with her big sister but the latter couldn't come. Moreover, Erika's sister asked her to get a phone strap for her. She entered in the cinema and thought Kuzumi would only watch some animes for kids. Later, Kuzumi sat next to her. She was shocked because she wasn't expecting Kuzumi to watch a romance movie. During the movie, Erika noticed Kuzumi was playing with his strap (a bird). At the end, Kuzumi fell asleep on Erika's shoulder. After the movie, Erika saw Kuzumi looking for something and realized he lost his strap. Then, she launched hers on Kuzumi, instead of giving it to her big sister.
Later, Kuzumi helped Erika when she was in an embarrassing situation. Many people were surrounded Erika because of rumors she was getting married to a rich guy. He broke a window to draw attention on him and help her to get rid of the rumors. Then, when Erika thanked him, Kuzumi told her they were even and left.
On Valentine's Day, Erika made chocolates for Kuzumi but when she went to give him, she saw Wakana Narita giving her own chocolates to him. Erika finally left without giving a chocolate to Kuzumi. But then, the day after, Wakana explained she just respected Kuzumi as well as she admired Erika. Later, Erika went to her locker, while thinking about Kuzumi, and saw him behind the lockers. She inconsciously called him out and then he looked at her. But she is interrupted by Kuzumi's belly gurgling so she gave him a black sugar candy. Then, Haruna came and asked Kuzumi if he would give him his candy. He tried to reach the candy from Kuzumi's hands many times in vain. Kuzumi frowned (it shows the candy Erika gave him is precious, he can't even give it to his best friend).
When they became second years, Erika opened the class' door and saw Kuzumi, sitting at the same seat, staring at her, then she closed the door. They were in the same class again, at the same seat. When she sat, Erika told him "Morning" and then Kuzumi answered "Let's get along for another year".
While they were hanging out at the beach with Yukko and Haruna, some guys came to flirt with Erika and Yukko. Kuzumi, who tried to break a watermelon, hit those guys. According to Yukko and Haruna, Kuzumi did that because he was jealous Erika was approached by other guys.
Later, Kuzumi disappeared and Erika found him far away from the place they were together. Erika asked Kuzumi what he wanted to do in the future and told him whatever it could be, it would certainly be something weird or impossible stuff. Kuzumi said it was none of her business. Then, the two of them became more distant until the end of the school trip when Erika apologized to him when he pretented to be sleeping. He accepted Erika's apologies and everything came back to normal.
For Kuzumi's birthday, Erika first bought a striped shirt because she noticed Kuzumi wears gym clothes at home. She finally gave it to Haruna who had no idea of what to buy for Kuzumi as a birthday present. Erika bought a bird doll instead and put it in Kuzumi's locker. Kuzumi noticed her, hidden behind the wall.
When Erika confessed to Kuzumi on Valentine's Day, this one ran away from her. Then, she decided to forget about love and to focus on her studies. She was even wearing glasses. The same day, during P.E., Kuzumi received the ball in the head and had a nosebleed. So he went to the bathroom. Erika followed him and hid behind the wall to tell him to forget she confessed if he wanted to. She also said she was sorry for bothering him. She left the room before Kuzumi could see her. He seemed to be a little frustrated not to can talk to her, neither see her.
Not so long after, Tooru Misaki and Kuzumi had a fight about Erika. This fight made Kuzumi realize his feelings for her, thanks to Tooru. Plus, the two boys already confronted each other a little while ago in a basketball duel (i think) for Erika.
Erika hung out with Yukko and Haruna at the mall. Yukko and Haruna saw Kuzumi with an unknown woman and decided not to tell Erika about this, knowing it would be difficult for her to hear when she's still heartbroken. Finally, Erika found Kuzumi, by chance, and saw him wearing a costum, with hat and sunglasses. He approached her with a bouquet of flowers. The woman who was accompagnying him appeared ; it was Erika's big sister who helped Kuzumi getting relooked for the White Day to thank Erika for the Valentine's chocolates she gave him. Erika told her sister Kuzumi's outfit was creepy.
Erika misunderstood the reason Kuzumi was wearing an elegant outfit. Then, she told him they could come back to normal and she wouldn't ruin this friendship anymore. Kuzumi didn't say anything but was quite disappointed and hurt by seeing Erika wanting to be nothing more than friends. The others tried to explain Kuzumi's real intentions (to show his feelings for her) in vain.
Since they became third year students, Erika and Kuzumi swapped their roles. Now, Kuzumi is stalking Erika while the latter doesn't seem to pay attention to Kuzumi. Hearing by some first class students fan of Erika that she was in the courtyard, Kuzumi joined them. The three first class students asked Erika to choose one of them to go around the cultural festival. They held out their hands towards her. Then, Kuzumi appeared and took one of the three hands. Shocked, the three students asked him who he was. One of them recognized him as the guy who substituted for the prince role in the White Snow's play the last year, with Erika Sakura as the princess. They understood Kuzumi came to get in their way. One of them asked Kuzumi if he likes Erika. Then, Erika tried to justify Kuzumi's presence by telling he only wanted to save her from an embarrassing situation when he saw her being troubled. At this moment, Kuzumi answered to the first year student he does like Sakura and then looked her in the eyes. The other students couldn't think Sakura would accept his feelings so they continued to laugh at Kuzumi. She felt embarrassed by this revelation and couldn't answer. Kuzumi approached her and it seems like he was going to kiss her.
Someday after, during the cultural festival, Erika was cooking with her class for their stand. She couldn't stop being thinking about Kuzumi's confession and wanted to give him an answer but was interrupted by an order 5 takoyaki. There were many people because of Erika Sakura's and Tooru Misaki's popularity.
When she finally had a break from her work at the stand, she hurried up to join Kuzumi on purpose to confess to him. On the way, she practiced her confession to be ready at the moment but ran into Kuzumi when she was saying "I like you" several times. Then, she told him to wait her there because she had to change.
After she changed, Erika came back where Kuzumi was waiting and proposed him to get crepes from class 1-4 fair but unluckily Kuzumi already went. Erika became embarrassed because she didn't know how to confess to Kuzumi. Then she sighed and apologized for this sigh, saying it is because she's tired.
One teacher appeared and asked some help. Kuzumi joined the teacher' side to help him but Erika held back of his arm because she wanted him to stay with her. The teacher and her fought about Kuzumi. Both the teacher and Erika were holding his arms. Erika told the teacher she needed Kuzumi because without him, there's no meaning. Then, she pulled Kuzumi and ran away with him. Kuzumi and Erika ran together, holding hands.
At first, Erika thought Chiba Haruna was propably a delinquent because of his red-tied hair and the rumors about him but then she saw Haruna with Kuzumi and noticed they get along very well and Haruna was probably more like a mother to Kuzumi than someone who could harass him.
Chiba Haruna saw Erika stalking Kuzumi many times but did not tell anything to him. He supports Erika's love for Kuzumi. Erika and Haruna even went to a shop to buy a present birthday for Kuzumi together.
Erika first met Wakana in the library. She sees her as an angel, who helps the others, and even directly calls her "Waka-chan". Wakana admires Erika for her beauty and her intelligence. But Wakana loves Kuzumi as well, so Erika and her are love rivals. When Wakana was rejected by Kuzumi, Erika was sad for her and cried a lot with her on Valentine's Day. The day after, Wakana tried to console Erika because when she confessed to Kuzumi, this one ran away. Wakana and Erika are good friends and don't hate each other for being in love with Kuzumi. They respect and admire each other.
- She has an older sister who is also popular with guys.