Hibiki is the eldest child of Misuzu & Jin Inukai and is a distant relative of Shinji and is Shinji's succesor. However his mother was killed by a religious organization but it is later revealed that Otoha is actually Hibiki's younger sister.
Hibiki is the most mature member of the Guardians he is a third year student at Seinaru Private School and is best friends with Shinagu. Hibiki was raised with the belief that everything has some sort of logical solution, thus he believes anything can be solved by logic. Hibiki maintains excellent grades and enjoys reading and studying, Hibiki's hobbies consist of solving math puzzles & likes calligraphy. Also Hibiki is the student council president and is very good at presenting speeches. It is later that Amamiya Otoha is the biological sister of Hibiki who was put up for adoption after the death of his mother as his father needed one child to continue the Inukai legacy.
In the game in Hibiki's route Hibiki intially hates Saya according to him she has a helpless look on her face, but he also uses his powers on Saya. Eventually Hibiki starts to see Saya in a whole new light after seeing how much effort she shows, once when Hibiki comes into her home he realises how Saya has always been alone. Hibiki also cares very much for Otoha and will do anything to help her.
Hibiki is a tall young man with dark pink hair and green eyes with a pair of glasses and wears the standard male Seinaru Private School uniform. Hibiki's casual clothes consist of a black dress shirt a grey jacket over it, a pair of black pants with a white belt and a pair of white shoes to conclude.
At first Hibiki proclaimed that he hated Saya and sometimes used his powers on her in order to allow her to see her own potential as the Tamayori Princess however after a while when it came to fighting etc. He walked her home and Saya invited him inside for snacks and tea whilst in there Hibiki noticed how bare her whole apartment is and he finally realised that Saya has been alone all her life afterwards he started to see her in a new light. In "Piece of Future" anime believably Hibiki shows some "affection" towards Saya that he has never shown to other girls not even his own sister Otoha.
Shirou & Hibiki are good friends however Hibiki can only be astounded by Shirou's behaviour at school and around Saya and can only wonder how he passed elementary school. Whilst Shirou finds Hibiki to be somewhat monotone and thinks he should lighten up a little plus considering how popular he is with girls can make other guys envious. Shirou would ask a question most of the time having to deal with Hibiki refusing to answer saying that he is not obliged or being confused by his long and complicated explinations. Shirou and Hibiki have a good relationship with one another.
Otoha and Hibiki are biological siblings and haven't spoken to each other in years however it is shown that Otoha cares deeply for her older brother and was unhappy that she had to be seperated from him once her mother was killed. Hibiki denies that he cares for Otoha however when she was in danger he went to save her but also to try and convince her that JSEI didn't kill their mother it was the church after this event. The two start to get along and maintain a brother-sister bond.
Shinogu and Hibiki are best friends he and Hibiki are in the same class and are both class representatives as well as members of popular clubs at school. Also despite Shinogu's density when it comes to girls, Hibiki is aware that he has a fan club devoted to him as well as Shinogu. Hibiki sometimes chooses to Shinogu about his feelings for Saya which really annoys him however despite this Shinogu retorts by teasing him about what he was like when he was in Middle School which makes the rare occurance of making Hibiki lose his composure.