Shun is the oldest of two children and has a younger brother called Chihiro. He is a distant relative of Mahiro Atori and is next Guardian to be a descendant of the raven. He has been best friends with Rei Komura since they elementary school.
Shun is a shy and calm individual who often keeps to himself and is a second year student. Shun gets good grades and is very skilled at studying that he tutors younger children. Shun's hobbies consist of gardening and poetry. In Shun's route in the game the protagonist (Saya) learns that Shun's younger brother Chihiro is very sickly and is hospitalised then that Saya learns that Shun is a very kind and caring older brother. Shun is overall very kind, caring and also very respected by many. He is best friends with Rei Komura and is the complete opposite to him. It is revealed in Piece of Future (Shun Route) that Shun fell in love with Saya at first sight considering he hardly interacts with girls, Saya was his first female friend.
Shun is a handsome young man of average height and has shoulder length blonde hair and has green eyes he wears the standard Seinaru Private School uniform. Shun's casual attire consists of an olive green t-shirt with a green jumper over it and wears a beige jacket over his jumper, with navy trousers and wears a pair of dark green shoes and wears a brown & gold necklace.
Shun during his childhood never interacted with his female classmates and Saya was his first friend who was a girl which made him a little shy. He first met Saya in the school greenhouse and she commented that the plants were pretty which made him happy to hear, he is very kind to Saya and is shown to have a good friendship with her and his younger brother Chihiro took a quick liking to Saya and even called her his "Girlfriend" much to his embarassment. It is later revealed that Shun is in love with Saya and in Piece of Future it was revealed that he fell in love with her at first sight.
Rei is good friends with Shun and they often split up together when patrolling the city. Shun and Rei have known each other since elementary school and are polar opposites to one another. Rei is aware of Shun's situation with his little brother and supports him and shows him concern whilst Shun can be concerned when it comes to Rei's behaviour at school and how he likes to bend the rules whilst Rei can often envy Shun because he wasn't forced to be apart of the JSEI until now whilst Rei had to be apart of it since he was a young child. Rei and Shun have very good team dynamics but also team up a lot when it comes to fighting or patrolling the area.
Shun and Touma are shown to be good friends despite Shun's reserved personality and Touma's typical tsundere one they are shown to get along. They act like a pair of siblings sometimes when Shun tries to persuade Touma to be a little nicer to Saya but Touma feels sympathy towards Shun when it comes to his situation with his younger brother Chihiro, Touma says that sometimes he envies Shun for having a brother and secretly wishes that he could have one himself.
Chihiro is Shun's younger brother who is very ill and is confined to the hospital, Shun promised that he would visit Chihiro in the hospital everyday however what Shun didn't know that was because of his spiritual powers that what was causing Chihiro to be ill. Chihiro plays a signifigant role in Shun's route he was later kidnapped by the Church and witnessed Shun use his powers and called him a monster and claimed that he wasn't his brother which broke Shun's heart. However when he rescued Shun the two brothers made up and later after all the Guardians lose their powers Chihiro started to recover immeadiatley.