Yin-Yang! X-Change Alternative is a Japanese erotic game produced by Crowd and distributed in English by Peach Princess. It is an offshoot of the popular X-Change series, but plot and storyline are entirely different and have no connection at all.
Kaoru Sakurazuka is a normal Japanese young man, not unique in the least except for his oddly feminine facial features, which drive him crazy. His name doesn't thrill him either—Kaoru is a common name for both girls and boys. He tries to make up for looking like a girl by wearing an extra coating of male bravado wherever he goes. He enjoys his time at school with his friends Touya and Renji.
In the game, Kaoru begins to have dizzy spells. After going to the school nurse—who's also famous for inventing new concoctions in the name of science—and accidentally drinking a vial of experimental medicine, Kaoru is shocked to wake up the next day to find that he's been transformed into a girl.
- Kaoru Sakurazuka (桜塚 薫/カオル?) - A normal, 19 year old, Japanese youth who has never had much to do with girls and is sure he'll die a virgin. He has a complex about his effeminate features and his unisex name.
- Mizuki Asakura (朝倉 瑞希?) - Kaoru's classmate. She's secretly in love with him, but is unable to confess her feelings. Age 19.
- Sakuya Kamishiro (神代 咲夜?) - Kaoru's classmate, and a friend of Mizuki. A stylish girl who gets good grades and is good at sports, her family owns a famous Shinto shrine, where she helps out by working as a Shrine Maiden. Age 19.
- Miu Kotosaka (琴坂 美羽?) - Kaoru's stepsister, the daughter of Kaoru's stepfather. Her last name is different from Kaoru's because Kaoru decided to keep his old last name in honor of his deceased father. She's secretly in love with Kaoru. Age 18.
- Kyoka Saionji - Daughter of a famous family, Kyoka was raised with nothing but the best a girl can have. Popular with the other students, she can't keep her hands off anyone she considers to be cute, whether they be male or female. Age 19.
- Touya Sakaki - A close friend of Kaoru's, he and Renji are always hanging around. He doesn't have a girlfriend, and is a virgin, like Kaoru. He has a rock band that specializes in doing covers of others' music. Age 19.
- Renji Saotome - Kaoru's other close friend. He's not especially handsome, but he's got a confident personality, and doesn't have a problem finding girls to date. He likes cute girls, and doesn't really care much about them as long as they're cute. Age 19.
- Rui Nanami - The servant of the Saionji family for generations, Rui is always at Kyoka's side, guarding her from harm. Age 19.
- Yui Nanami - Twin sister to Rui. She is also always guarding Kyoka's person. Age 19.