Yamanaka Kurumi

Hobbies: Knitting
Skills: Baking
Likes: Penguins (Collecting goods)
Dislikes: Getting birthday and Christmas presents at the same time
Favorite food: Sweet foods, whipped cream
Hated food: Spicy, tough foods

Shotarou's non-blood-related younger sister who calls him "onii-chan" and lives with his family because of an accident where her parents died when she was younger. After moving in, she was often depressed, but Shotarou managed to cheer her up through various means. Kurumi is also the reason why Shotarou turned into such a hotblooded man who only spouts dumb words. Thanks to him, Kurumi opened up and became a more cheerful person, but is still very clumsy and loves penguins, and tries to support her onii-chan the best she can.