Kasumi Ishiki is the main protagonist of this story, and is voiced by Kana Hanazawa . Kasumi was diagnosed by the Medusa virus along with her twin sister Shizuku. 160 people out of the world were chosen to be cryogenically frozen until a cure was found, and Kasumi was one of those few selected. She is devastated by the fact that Shizuku was left behind, and the mere thought of leaving her to die.
Kasumi has short black hair with a fringe, and wears round glasses. She is often portrayed with brown eyes, however as seen on the volumes covers her eye color varies to a brown, a grey, blue and even yellow. When she is first seen Kasumi is wearing a pink t-shirt and pants, which were given to all the 160 people that were to be frozen in either blue or pink. Later on in the series her original outfit became ripped and torn, so it was swapped with a black dress that cuts off at the knees, with a white button-up shirt, given by Ron.
"'God is cruel. Even though he knew we were twins... He only chose one of us..." - Kasumi Page 1 volume 1Edit
Kasumi is a shy and gentle girl, and thinks herself to be the polar opposite or her sister Shizuku. As the series progresses she gains more confidence, though all along willing to risk her life. It is shown that she was at a stage where she wanted to commit suicide because she could not live without Shizuku. Where she cut herself with a razor, before Shizuku stopped her altogether.