Seiji is a more-or-less level headed individual, trying to please all the women around him without hurting them. He, like all the others except for Guri, are minor angels as Guri made them all into a relationship together. As a result, they are all effectively immortal (But they still feel pain) and if Guri fails to do her job all the people connected to her this way will cease to exist altogether.
Seiji is a light-skinned guy, has blue pointed hair, has large eyes with tiny blue pupils. He is usually seen wearing a school uniform consisting of a white long sleeve t-shirt, black pants, black-red diagonal striped tie and green tennis shoes with yellow and white parts.
Seiji is a fairly level-headed individual that was just a normal high school student before meeting Guri. Although he only has romantic feelings for Akane, he does care about the rest of the harem as shown by how he frequently protects Yuzu and went on a daring rescue mission to hell to save Guri. Despite Akua's often hostile demeanor to him, he cares a great deal about his little sister and risked his life on two occasions to protect her from Stolas.
Although wary of Shikimi, he is willing to cooperate with her when the situation warrants it.
"I'm Getting In on This, Too x Whoa! Forbidden Love?!"
A strange girl named Guri arrives at the house of Seiji Aino with a notebook called the "Kiss Note," which has the power to cause love between people. She claims that if Seiji does not kiss someone within 24 hours, he will remain a virgin forever, which Seiji misunderstands so he kisses her instead. The next day, Seiji's crush, Akane Hiyama becomes jealous of Seiji and Guri's apparent relationship, and attempts to murder them both with Gurkha knives. The two eventually make-up, with Guri revealing her status as a cupid from heaven, and pairing them together with the Kiss Note, but not without including herself into the harem. Later, Guri's boss, Korari possesses the body of Seiji's cat, and informs Seiji that as he and Akane are technically in a relationship with Guri they have become immortal and must help her complete her duties as a cupid or risk being sent to hell. At school, a mysterious girl steals the Kiss Note, and is later revealed to be Yuzu Kichougasaki, Akane's younger half-sister, who has magical telekinetic powers and also happens to be obsessed with Akane. Yuzu is ultimately incorporated into Seiji's harem by Guri as well.
"Sniff Sniff x The Only One Who May Hurt Seiji-kun... Is Me"
Akane meets Seiji's sister, Aqua. Guri and Yuzu use the Kiss Note to pair up random students so Seiji confiscates the Kiss Note. One of their teachers Mr Kusunoke, is in love with one of their classmates, Mari. The girls decide to find out if the two would make a good couple, despite being a teacher and student. Mari claims to think of Mr Kusunoke as a little brother. Guri plans to fake taking Mari hostage so Mr Kusunoke can rescue her, however real criminals take both Mari and Guri hostage and Seiji is shot protecting Yuzu, causing her to develop feelings for him. Mr Kusunoke tries to protect Mari but is too weak to be of help. When Akane realises the criminals shot Seiji she beats them violently. Mr Kusunoke tells Mari that to confess his love would be inappropriate and will wait until she is no longer his student. Mari reveals she feels the same way but had likewise been waiting to tell him. She also privately tells Seiji that she loved Mr Kusunoke first and secretly manipulated him into falling in love with her. Aqua jealously watches Seiji with the girls.
"I Can Handle This Myself! x Wassup"
Aqua learns her brother has 3 girlfriends and punishes him. Yuzu attempts to befriend Aqua but Aqua accidentally reveals her own feelings for Seiji. They are approached by Stolas, a demonic penguin obsessed with Aqua. Seiji saves Aqua while Stolas is arrested. Guri and Seiji observe an argument between a man and the women he was cheating on. Seiji gets pulled into the fight and the Kiss Note is burned. Korari admits that as no Kiss Note has ever been destroyed before no one knows what will happen. After Akane ignores Seiji it is concluded that all the couples brought together by the Kiss Note will break up, including Seiji and the girls. They are approached by Tiara, another cupid and friend of Guri's who shows them all the other couples are still together. She gives Guri her own Kiss Note as a replacement as she is retiring due to being pregnant. Akane appears, angry that Seiji had not chased after her like she wanted and kisses him before stabbing him. Fortunately Guri re-enters their names in her new Kiss Note, restoring their harem and immortality just in time. A pink haired girl in glasses watches them.
"I'm Not Going to Lose! x Are You Like Me?"
As a child Yuzu's mother orders her to stay away from Akane. Guri learns Yuzu skips school so she can stalk Akane. Akane admits she knows Yuzu stalks her and tells Yuzu to attend school since she has Seiji to protect her, which upsets Yuzu who runs away. Yuzu defends herself from a pervert and falls into the water until Seiji rescues her. Yuzu admits that she hates herself because Akane fell in love with him instead of her and swears to one day win Akane's heart. A girl named Shikimi approaches Seiji and Guri for help with her crush. Guri is unable to write the crushes name in the Kiss Note as Shikimi does not know his name. Seiji ends up alone with Shikimi and accidentally reveals that he and the girls are immortal. Guri realises her Kiss Note is missing. Shikimi lures Seiji away and kidnaps him, revealing that she is actually the pink haired girl from episode 3, a sadistic psychopath who has stolen the Kiss Note and tortures Seiji to find out how Guri grants immortality. Guri tells Yuzu and Akane Shikimi's name, which terrifies Yuzu and further enrages the already violently jealous Akane.
"What Is Love? x Kami Is Prostrating Himself Now lolol"
Akane reveals that Shikimi is her and Yuzu's cousin. Shikimi restrains Akane and threatens to kill Seiji to hurt Akane. Guri appears and Shikimi tries to manipulate her into letting her join the harem. Guri refuses as she can sense Shikimi's heart is devoid of love. Shikimi receives a call from Akane's mother and leaves but swears to one day join their harem. Seiji suddenly dies and goes to Heaven where Korari informs him he is to meet with God, a middle aged geezer named Kamisama, who is also Guri's father and spends his time keeping tabs on Guri via a television in his room. Kamisama explains that as Guri is his only child she will one day replace him as God so he insists Seiji teach Guri about true love since Guri still doesn't understand anything about it. Their meeting is interrupted by Maou, the current ruler of Hell who is determined to make Guri work for him as a demon. Seiji claims Guri wouldn't be interested as she is too free spirited. Kamisama and Maou agree Guri is still too immature and Seiji is returned to earth to teach Guri all he can about love.
"Go to the Beach With Me? x It's Not a Matter of Knowing or Not"
Seiji invites his sister and the girls to the beach. At the beach Guri throws a volleyball into Akane’s cleavage beginning a volleyball war. Seiji realises Shikimi has followed them. Shikimi blames Seiji for making Akane weak and explains that Akane’s family are magical spear users while Yuzu’s are magical shield bearers and the two families are in the middle of a feud started by Akane and Yuzu’s mothers over Akane and Yuzu’s father. Shikimi is convinced Akane is too weak to survive the feud. This is proven true as Akane fights Stolas, who has returned for Aqua, and is badly injured. At school everyone attempts to help a couple prove their love by hunting ghosts. However it turns out the couple were also ghosts who had fallen in love but other jealous ghosts had refused to let them go to heaven until they proved their love. After helping the ghosts Akane asks Guri if she truly loves Seiji, and if she doesn’t, to leave Seiji alone as she would just be getting in the way of Seiji’s happiness. Guri is left troubled by her own feelings.
"It's a Festival x How Did It Come to This?!"
Guri becomes angry when Seiji refuses to go to a festival with her. Guri is approached by a boy who asks her on a date. Guri constantly compares Seiji with the boy who is much nicer. At the festival the boy tries to kiss her, only to be rejected as Guri cannot stop thinking about Seiji. She then bumps into Seiji who came to the festival to stop her complaining. Despite his bad qualities she kisses him after realising she is happiest when they are together. The boy is revealed to have been under mind control by Maou to see if he could ruin Guri and Seiji’s relationship. Akane’s mother, who believes love leads to weakness, orders Akane to break up with Seiji. Seiji is attacked by assassins but Aqua saves him. Seemingly imprisoned Akane recalls her childhood, the first time she met Seiji and how she eventually fell in love with him. Shikimi tells Seiji the assassins work for Akane’s mother and she has locked Akane up in the family home as punishment for falling in love. Following Shikimi’s urging Seiji, Aqua, Yuzu and Guri decide to help rescue Akane.
"Farewell x We're Rivals, Obviously!!"
At the Akane household Akane tries to get Seiji, Guri and Yuzu to leave before fighting with Guri who threatens to steal Seiji unless Akane stops her. Akane’s mother, Suo, appears while Shikimi captures Seiji. Suo orders Akane to kill Seiji. Akane almost does so but cannot as she loves Seiji too much. Suo almost beheads Seiji herself but Akane saves him. Before Akane can fight Suo, Yuzu’s mother, Ameisha, arrives and duels Suo instead. Akane and Yuzu explain their mothers were once in a relationship with the same man, Akane and Yuzu’s father, and were good friends, but the relationship ended badly, resulting in their family feud. Akane stops the fight by insisting she is staying with Seiji no matter what. Guri points out Suo is acting out of love and is subsequently stabbed in the head by the embarrassed Suo, who allows Akane to continue dating Seiji, on condition she will kill him if he ever hurts Akane. Akane, back to her old self, attacks Guri for kissing Seiji and declares that they are now rivals. Suo explains to Ameisha that Yuzu is in love with Akane while also dating Seiji, something Ameisha had been unaware of.
"Absolutely... Nothing... x There's Just Something Wrong With Me..."
Following the previous episode Akane and Guri argue constantly. Guri worries Seiji and Akane are leaving her behind. Shikimi is ordered by both Suo and Ameisha to keep an eye on Seiji. Seiji and Akane plan to show Shikimi their success as a couple. Akane suggests they kiss and Seiji agrees on condition Akane and Guri get along. Yuzu becomes upset at the thought of Akane and Seiji kissing. As part of the cultural festival the class decide to put on a play with Shikimi, Akane and Guri as the Princess, Knight and Knights Rival respectively. Yuzu kisses Seiji, becoming confused when she feels nothing and convinces herself she hates Seiji for stealing Akane. During the play Akane fights with Guri again. Yuzu arrives and admits to kissing Seiji to work out how she feels. Akane forgives her, telling her to take all the time she needs. Akane successfully finishes the play by kissing Guri, hoping to show Seiji she can get along with her if necessary. Yuzu claims she still detests Seiji but no longer hates him. Shikimi mentions to Guri that the closer Yuzu and Akane become to Seiji, the more Guri risks being left behind.
"I'm Here to Stay the Night x I'm... Growing Up, Too"
Seiji is happy to be spending time by himself, only for Akane, Yuzu, Guri and Shikimi to all turn up at the same time. After spending the day with them Seiji tries to take a bath but his privacy is repeatedly invaded. Later with Akane in the garden Seiji keeps his promise and kisses her. At night the girls all sleep in Seiji’s room while Seiji sleeps in the living room, however in the morning all the girls have moved into the living room with him. Aqua returns, sees Seiji with four girls and punishes him. Seeing Aqua is upset Guri promises to help Aqua get some attention from Seiji. Aqua questions whether Guri has any actual feelings for Seiji. Stolas the Penguin returns, stronger than before. While escaping Aqua is defended by Korari. Aqua, tired of being afraid, stands up to Stolas and kicks him in the face. Seiji arrives to protect Aqua but finds she no longer needs protecting. Aqua realises her brother is still the same person he always was, despite his multiple girlfriends. Guri worries that something is missing between her and Seiji. Shikimi offers to talk with Guri about it and they disappear together.
"Where Did She Go? x I Apologize for Troubling You Until Now"
Guri has been missing for over a week and Korari is concerned Seiji is not taking it seriously. Seiji suspects Shikimi is responsible and confronts her. Shikimi captures Seiji and kisses him with Guri secretly watching. Guri had confided in Shikimi her fear something was missing between her and Seiji. Shikimi suggests staying away from Seiji and observing him with Akane. Guri saw that Seiji did not seem to be looking for her. Akane and Yuzu arrive and Shikimi reveals the depressed Guri. Shikimi tells her to ask Seiji how he feels about her. Seiji angrily responds that Guri has only ever been a nuisance, causing Guri to become cocooned in black feathers. Maou appears, having been working with Shikimi to manipulate Seiji into breaking Guri’s heart so she would fall from heaven and be reborn as a demon. The new demon Guri nonchalantly announces that the old Guri is dead and it is Seiji’s fault, then leaves to begin breaking up all the couples she ever brought together. Shikimi leaves with Maou. Yuzu blames Seiji for neglecting Guri and insists he help her save Guri. Akane refuses to help while Seiji decides he also wants to save Guri.
"Right, Let's All Die! x I Finally Understand"
Kamisama suggests Seiji and Yuzu go to hell to retrieve Guri. Guri refuses Maou’s offer to become the new Satan so he can retire. Seiji and Yuzu are found by Shikimi, forcing them to flee. They are rescued by Akane, who reached hell in an unusual manner, and after reaching Guri demands she either return to normal or stay a demon forever. Seiji finally realises how badly he really had been treating Guri and pleads with her to return to normal. After Guri instinctively makes a dirty joke Seiji realises normal Guri is not gone after all. Shikimi explains Guri’s plan to disappear and the pain she felt when no one seemed to miss her. Guri becomes so confused by her feelings she almost faints. Seiji, following advice from Kamisama, asks her what she really wants. Guri’s demon wings are suddenly replaced with angel wings as she returns to normal, having realised she wants Seiji to love her and kisses him. The heartfelt moment abruptly comes to an end when Akane, furious at the kiss, throws a knife at Guri’s head. With everything back to normal Guri promises to add Shikimi to the harem if she gives love a try.
- In Japanese, Aino means 'love of', also blue.
- Seiji [sei-ji] as a boys' name is pronounced SAY-jee. It is of Japanese origin, and themeaning of Seiji is "lawful; manages affairs of state".