Byakuda No Hanamuko summary:

A white snake who is a divine messenger and a childhood friend with a mystery. Entangled obsessions in a Japanese-style fantasy.Tsubaki, a high school student with a predisposition for bad luck, has a one-sided love for his childhood friend Sakuya, who is both beautiful and talented. Then, one day while leaving school they are randomly attacked on the street.In the ancient capital Kyoto, a lovestory defying fate unfolds.(Source: Young Champion Web, translated)