Riiko Izawa is the protagonist in the main series Absolute Boyfriend by Yuu Watase.
Riiko Izawa is a young girl struggling with accepting herself and embracing her shortcomings. Known for being a little odd and a lot flat chested she is constantly rejected by guys. Riiko ends up finding a cell phone that belongs to an odly dressed man. Talking more to herself than him, she mentions her lack of a boyfriend and how much she really wants one. The man quickly points her in the way of a website in which he works for that can give her what she "desires."
Skeptical, Riiko ends up visiting the site , Kronos Heaven, out of curiosity. The site is a create your on lover site! Riiko, under the impression that it is a game, goes through the whole process filing out everything she wants and dreams of having in a guy. She expects none of it to come true. The situation is all a little bit sad as she realizes how low she must be to resort to create your on lover sight that has absolutely no outcome, so she thinks. When she is done, she clicks the end button and successfully filed for a free trial of a nightly lover figure. Of course, Riiko is still oblivious as to what she just got herself in.
The next day a huge package arrives at her door and out comes a naked man! He absolutely stunning and Riiko is dumbfounded. She finds the instructional manual doing exactly as it says she kisses him. The kiss makes his system instantly connect with Riiko and cause him to wake up and be in love with her. She loves him; he is perfect and does everything with her in consideration. Naturally, she is shocked and sad to find out that he was not her's to keep but only a 72 hour free trial. In order to keep him, it would cost 100,000,000 yen! Riiko is desperate to keep him, begging if there is any other option. Since the nightly love figure is relatively new, the site has yet to work out all of its quirks and is in need of major data. Riiko offers to give data about how women think in feel in return for her keeping Night.
Her life takes a surprising turn now that she has Night. She must find a way to keep going to school and keep Night's secret of not being entirely human to everyone else. But, that can be really hard when you have a severely abrasive and nosy neighbor. Riiko is neighbors with Soshi Asamato. Soshi has been her childhood friend for as long as she can remember. But, she mistakes his care and worry for her to be brotherly when in actuality he loves her and has always loved her. Soshi is also her boss at the restaurant she works at.
Despite as much as she fights it, Riiko enters a love triangle that involves herself, Night, and Soshi. Night ends up developing actual human feelings for Riiko, he loves her just a human would. But, his system is not made to do this or handle any actual emotions. Inadvertently, his love for Riiko is hurting him. Riiko confronts her feelings when she is faced with the realization that she might lose Night. It is in his near death, she admits that she in fact also loves Night. She apologizes to Soshi, who had moves in with her and Night out of fear that he was losing her. Soshi is heartbroken and can't take it. He immediately moves to Spain with his father as to not hinder Riiko and what her heart truly wants.
Riiko and Night enjoy their time together as an official couple in love. The go out, buy rings, and get their picture together. She is truly happy with Night and he is with her too. But, as time goes by Night begins to get Sleepier and Sleepier. It is as if his energy is depleting by the day. Riiko is completely shaken to a whole new level. Night’s body shuts down and stops working do the fact that his mind was exceeding his physical capabilities. He loved Riiko with all of him, and his body could not take it. Before he died, Night wrote a letter to Soshi in Spain. The letter describes what is happening to Night, who knew near the end that he would be leaving. He simply asks Soshi to take care of Riiko. Night also sent his ring to Soshi. Soshi comes back from Spain to take care of Riiko. Reading the letter, Night tells Riiku that she does not need to cry or be sad for him anymore. Riiko through tears smiles and cherishes the ring, letter, pictures and memory of Night her first and for always boyfriend.