You were in your brother Giyuu's room and you were playing together even though he had to study for the next day's test when all of a sudden a sweet female voice was heard calling you it was your sister Tsutako

Tsutako: What are you doing? she said with a gentle smile Giyuu you should study for the math test if you don't want to fail, you can't waste your time like that

Giyuu: don't worry Tsutako everything is under control he said not giving much weight to her sister's words