Inui Hiroyuki

Inui Hiroyuki is a second-year high school student at Morinomiya Academy.

Appearance
He is tall and has red, messy hair. He is only ever seen wearing the school uniform with his tie worn loose. On occasions when he helps Kotaro in secret, he wears a paper bag over his head that says, "Helper Mask".

Personality
If one were to ask Inui to describe himself, he'd say he's a pure-hearted, wonderful person worthy of respect. If one were to ask his classmates the same thing, they'd describe Inui as an idiotic, delusional jerk. He's a brash and blunt person, who openly speaks in his mind and acts impulsively. He leaves a bad impression on Ryuuichi initially by calling the daycare children annoying and calling Midori a "crap factory". He states that his type of girl is a soft, cute, fluffy girl. Since none of the girls in his class fit his type, he's openly stated that he doesn't consider them girls at all. Inui is oblivious to the fact that he comes of as incredibly rude when he shares these personal observations. When those classmates invariably get outraged and pelt him with rubbish, he completely misses the point of their anger in favor of feeling that their hostility justifies his opinions.undefined

He's a bit of a romantic who blushes easily when it comes to Midori's mom, Yukari, and girls that he likes in general, and he often plays out scenarios in his head with the object of his affections. Despite his general childishness, he's sometimes mature, like when his respect for the sanctity of marriage drives him to try and move on from his crush on Yukari when he learns that she is still a proud wife.

Inui is prone to immersing himself in wild misunderstandings, especially when it comes to romance. Like his error with Yukari, he wound up falling hopelessly in love with a girl who turned out to be Ryuuichi in a wig. He also came to the wrong conclusion when trying to determine who his sister had a crush on. Inui has even had the misfortune of being the victim of a misunderstanding that was beyond his control, having been mistaken for a dangerous criminal who intended to hurt Kotarou when he was only trying to help.

In his first appearance, he was shown to find children noisy and disgusting. However, with the numerous encounters he's has with the daycare children since then, he discovers a kinder side to himself. This emotional development towards kids has even extended to his daily interactions with his own little sister, Mika.

History
Inui appears in the daycare one day, rudely introducing himself to Ryuuichi and asks to meet Midori, Yukari's daughter. Under the misguided belief that Yukari is a widow, he expects to one day take the place of Midori's father when he eventually marries Yukari. He claims to have "high expectations for the child of the woman he loves", and is extremely disappointed when Ryuuichi reveals Midori is the baby that just relieved herself in her diaper and disgusted him. When Yukari arrives with the news of her husband's return which is confirmed by a bemused Usaida, Inui decides to give up on her half-heartedly. He still has lingering feelings for her, and Usaida manages to bribe him with a picture of Yukari in a bikini in exchange for secretly watching over Kotarou while the toddler journeys through the school to deliver Ryuuichi's forgotten lunchbox.

Inui becomes infatuated with Ryuuichi in a female disguise at the school festival and returns to ask him about the "gentle girl" that he met then. Kotarou immediately points at his brother, which was not picked up by Ryuuichi. Ryuuichi then suggests that it might have been Maria Inomata, and Inui requests Ryuuichi to set a date for him with her which was refused as it might trouble her. Inui claimed that his mind is "going crazy" and that Ryuuichi would not understand his feelings. Ryuuichi relents and promises a date with the "girl". Yayoi Kumatsuka, who saw the situation, claims that it was her responsibility to undo everything that she has done due to the wig and takes charge. Ryuuichi ended up with a wig and a female uniform, looking like a normal schoolgirl. Kotaro is shocked by Ryuuichi's drastic transformation whereas Kirin and Taka are both smitten by it.

The next day, Hayato and Ryuuichi as "Inomata" turn up together to meet Inui. Hayato claims "Inomata" as his girlfriend in order to break Inui's infatuation as part of Yayoi's ploy. Inui is sorry for the situation yet says that he is happy to have met "her". A guilty Ryuuichi decides to reveal that he was the girl Inui met, but trips over a squatting Kotarou and falls in Inui's arms. Inui turns red and stiffens in shock. In the end, Ryuuichi keeps the secret, compelled by how Inui looked like "Kotarou when he believed in Santa" and he "could not bring himself to say it".

Trivia

 * Inui has horrible luck with women. His first love was not, as he thought, a widowed mother but happily married to a husband who takes long work trips. He gets over Yukari only to fall for a girl who is actually Ryuuichi in a wig and girl's uniform.
 * He is oblivious to the fact that his classmate, Nekota, may have a crush on him.
 * According to a (joking) note made by author Hari Tokeino, Hiroyuki primarily exists because it's easy to write stories for him even when Tokeino is suffering from writer's block.
 * The "Inu" of Inui means dog.