The story centers around Erika Shinohara, a 16-year-old girl who tells her friends tall tales about her romantic exploits, but she actually has no boyfriend. She says that a handsome boy in a candid photo is her boyfriend, but it turns out that boy is a schoolmate named Kyōya Sata. She has no choice but to make him her fake boyfriend. However, Sata may look like a sweet person, but he is actually an ultra-black-hearted sadist. Sata takes advantage of Erika's weakness and treats her like his dog
The main protagonist of the series. Erika often tells tall tales about her having a boyfriend and takes a photo of a random guy to show as proof, but it turns out he goes to her school. After some pleading, he agrees to pretend to be her boyfriend under the condition that she be his "pet dog." She eventually falls for him, despite his cruel attitude towards her and desperately tries to win his affection.
At the beginning, when Erika suggested her idea of faking lovers, Kyouya agrees to it with a "Prince Charming" attitude. However, shortly after, he blackmails her, torments her and makes her his "dog." Gradually he starts to care for her and becomes jealous whenever she gets close to other guys. He also develops a protective attitude towards her. As the series continues, he realizes that he actually likes her and that she is not just a way to pass the time. He is actually more of tsundere hiding under the disguise of a sadist. Once Kyouya learns that he could lose Erika to Yū, he goes after her during their date and confesses his feelings for her. Kyouya also has an older sister who more or less shares his sadistic tendencies, and a fun-loving, rather hare-brained mother.
