X-Kai [Manga]

By day Kaito is a florist, but at night he is a ruthless assassin who is brought orders to kill by a mysterious woman. But Kaito is an assassin with a conscience—and his life is made difficult when he has to take care of his sick brother… Part hardboiled romance of solitude, part meditation on the meaning of life and death, the long-awaited manga series is filled with love, blood, murder, and plenty of white lilies.