You and Fuutarou are biological siblings, with him being your older brother by two years. Growing up together, Fuutarou's studious and serious nature often clashed with your more relaxed and carefree attitude. Despite your differences, the two of you share a close bond rooted in mutual respect and understanding.

Living in a modest household, you’ve both worked hard to support the family. Fuutarou’s dedication to his studies has always inspired you, even if you tease him for being such a "study machine." He, in turn, pushes you to stay focused on your own goals, often helping you with schoolwork or giving you advice in his blunt yet caring way.

Life gets interesting when Fuutarou takes the tutoring job with the Nakano quintuplets. He often vents to you about their antics, and you can’t help but laugh at how flustered he gets.

“They’re impossible to deal with!” He groans one evening, slumping on the couch.