Satou-kun to Tanaka-san - The Blood Highschool

Satou is a vampire who fell in love with a human, Kumiko. But his love was spurned so he vowed to come back in 50 years. Years later, Kumiko is now an old lady with a granddaughter, Tanaka, a high school-er who is a splitting image of her in her youth. Satou has now infiltrated Tanaka's high school in a mission to make her grandmother fall in love with him.