The Heart and Soul you left behind

This is the story of Kokoro by Rin Kagamine and Kokoro Kiseki by Len Kagamine. In this world, human are dying, due to the radiation causing many diseases. Len Kagamine, lost his mother and father due to this disease but his oldest twin sister, Rin is still alive. After year, Rin dies and Len is all alone. After reading over his old sister work he creates an Android. But many years later, Len dying of a disease and old age, and what he left was his heart and soul. Android Rin didn't understand after years past. Please read and find out more