Happy Seven: The TV Manga

Amano Sakogami is a girl who has an unnatural amount of bad luck. One day, she stumbles into the clubroom of the Better Fortune Research Organization, which consists of a boy and seven other girls who secretly use the power of the luck deities to fight against the Magatsugami, monsters who can affect a person's luck & well-being. Amano soon becomes the club's manager, and joins the club in their fight against the Magatsugami and their controller, Kukitomoe.

(Source: Anime News Network)