アステリズム -Astraythem-

I love my elder sister.. My love belongs to my elder sister... I'm in love with my elder sister... Sakurazuka Tsukumo has fallen in love. His beloved one is his elder sister, Sakurazuka Natsuki. When he was a child, she risked her life to save him in front of Death's scythe. Her face on that rainy day has carved into his heart and he swore to protect her forever, to ensure that she would never have to suffer again. Time went by, while he got stronger and stronger, she became more and more beautiful. Will Tsukumo be able to confess his feelings to her? Will they ever be able to become a pair of lovers? "My answer had already been decided on that day." [Translated from Getchu]