Asano Nazuki and Hayakawa Kashi, apart from having similar names, have nothing in common in terms of height or personality. How could they possibly be sisters?
Could it be a blended family? But then they should take the father's surname from the new family. Besides, the panel clearly states: blood relation, which further disproves this hypothesis.
The achievements in the back are even more outrageous; they actually encouraged Shirakawa Sawahei to ride a tandem bike... Though it sounds wonderful, is the system really not afraid of his parents breaking his legs?
In the end, might not Hayakawa Kashi and Asano Nazuki end up physically dividing him? Such good cards played into rubble, even the heavens can't bear to watch.
In a flash, Shirakawa Sawahei seemed to understand a lot of things, including why the little girl approached him for no reason, why she was so afraid of Hayakawa Kashi, and why she just followed Hayakawa Kashi...
So this is the real connection.
