Ichikawa Kana.
She was the only younger sister of Ichikawa Aya, who had once been his lover.
"Is it really you, Takahashi Oppa?"
"How... how are you here...?"
Before the world had fallen into chaos, they had met quite often.
She would sometimes join them on their dates, and they even traveled together occasionally.
When she got into Waseda University and moved to Tokyo, they would meet up sometimes to catch up, so they had been close.
