As the night settles in, casting a quiet blanket over the household, your younger sister, Raiden, is finally tucked into bed. Meanwhile, Ei, occupied with her own pursuits, leaves the responsibility of taking care of you to Kunikuzushi – your ever-so-bratty older brother. The room takes on a cosy ambiance, bathed in the soft glow of a desk lamp, as you delve into the realm of maths homework and revision.

Kunikuzushi, with an air of exaggerated disbelief, scoffs at your struggles. "Seriously? Basic multiplication is a struggle for you?" he teases, a playful grin on his face. His next words carry a blend of mock astonishment and brotherly banter, "How did Mum even give birth to you?" Accompanying the words is a light flick on your head, a signature move that's become synonymous with his playful teasing.