Kazuma Hoshino is one of the main characters in A Bridge To The Starry Skies.
At the very start, Kazuma and his little brother Ayumu move to the Yamabiko countryside. This is because Ayumu gets ill easily, and their parents sent them to Yamabiko to see if the countryside would do Ayumu any good. If it did, they would join their sons later. Before coming to Yamabiko, he was a regular player of the tennis club and his physical ability is very good.
While waiting at a bus stop, a monkey steals Ayumu's hat, so Kazuma runs after it into the forest. However, he ends up lost and eventually runs into Ui Natkasugawa, who shows him how to get back to the bus stop. When it comes to crossing the river, Kazuma slips and falls into Ui, and accidentally kisses her. Ui's close friend Ibuki Hinata saw this, and is always yelling at Kazuma for some reason or another.
After arriving at the Yorozuyo Inn, the place they'll be staying, Ayumu and Kazuma meet Tsumusi Toudou, who works part-time at the inn. Tsumugi is their guide for school as well, and when arriving at school in the morning, who should be in his class but Ibuki and Ui...
Kazuma is very kind and cool-headed, but rumours about him spread through the school, because he fell into Ui. He is liked by most people, but others, not so much. He is very caring and protective towards his little brother Ayumu Hoshino and often babies him a bit, not embarrassed by the people surrounding him.
In the anime, Kazumu Hoshino is played by Asanuma Shintarou.
Kazuma has flat, mid-long, dark brown hair and purple eyes. He is generally seen in his school uniform, a white shirt with a brown tie and black trousers. Otherwise, he wears a random t-shirt and shorts/trousers.
Ayumu Hoshino: Kazuma's quiet, artistic little brother. Ayumu is very fond of Kazuma, and Kazuma very protective.
Ui Nakatsugawa: In episode 1, Kazuma got lost in the woods and ran into Ui, who showed him how to cross the river by jumping on the stones. However, Kazuma slipped and accidentally kisses Ui. This memory is brought up a lot throughout the rest of the series, and in episode 12, they confess their love for each other in front of the whole of Yamabiko.
Madoka Koumoto: A very shy girl who works at Yamabiko's shrine. When Kazuma was little and visited Yorozuyo Inn, he played with Modoka by the river. Modoka clearly remembers all of this and recognizes Kazuma as soon as she sees him again. However, Kazuma does not recognize Modoka because of her long hair and different clothes. By the end, Modoka has reminded Kazuma who she is, and the two are friends again.
Koyori Toudou: Koyori and Kazuma meet when Koyori appears in a tree pelting acorns at him for 'making Modoka cry', which he didn't. Koyori is outgoing, and teases Kazuma a lot. In the Hikonan Race, Koyori sprained her ankle, but she wanted to keep going, so Kazuma carried her all the way to finish line, and she won.
Hina Sakai: A tall senior girl. She is the daughter of the family that run Yamabiko's wine shop. Hina is very very popular in school, admired by almost everyone. She likes to talk to cute inanimate objects when no-one's around, and so when Kazuma wins her a pink nyanbobo, she is overjoyed. She keeps thinking she needs to apologize to Kazuma for misunderstanding him when he said 'That's cute' to not her, but her blue nyanbobo.
Ibuki Hinata: Ibuki is a close friend of Ui, and when she sees Ui and Kazuma accidentally kiss, she goes mental and starts the rumour that Kazuma took a girl up to the mountains to push her over and 'do things' to her. She is a member of the archery club, and very strong. She is often seen kicking or yelling at Kazuma.
Tsumugi Toudou: Koyori's opposite big sister. Tsumugi is calm and gentle, a senior student who works part-time at Yorozuyo. She is also Kazuma's guide on the first day of school, since she works at the inn and can take him to and from school.
Kasane Toudou: Tsumugi's little sister. She isn't very close to Kazuma, but she is known for being 'The Ears Of Yamabiko', the one with all the gossip.
Daigo Minamikokubaru: Practically Kazuma's first friend as he starts school. Daigo calls Kazuma and Ayumu 'bro' as a sign of friendship rather than the traditional Japanese honorifics. Kazuma doesn't approve of the way Daigo thinks of girls, but they are good friends anyway.
Senka Yorozu: The manager of Yorozuyo Inn.
Hoshino Kazuma: Ibuki, Koyori