Manga Like Shounen Shoujo

The story centers on an 11-year-old boy who hates the lack of unique individuality in the world, and hates that he himself lacks individuality. One day, he finds that everything that might give a person individuality — such as their faces, names, and personal information — have been erased from his sight, as if by a marker pen. He later learns that this is a fatal disease, and that he will not live past 12. He rejoices, having acquired the unique trait of "tragic main character," and moreover takes great pleasure in being the first to die from this disease so the disease will be named after him. At least, until a girl appears with the same disease. He quickly becomes disappointed that the girl seems to have a more unique spark to her, and her life expectancy is even shorter than his. To top it off, he learns that the disease might end up being named after her. He resolves to kill her before that happens.