Nakagami-ke no Ichizoku

Haruka Iijima and Tokio Nakagami are student and teacher... and star-crossed lovers! If their forbidden relationship weren't enough trouble, they also have to deal with the rest of Tokio's family, the strange and insane Nakagami Clan! Not only are the Nakagamis all devastatingly gorgeous and apparently ageless, they're all completely obsessed with Tokio- and that means nothing but trouble! Can Haruka and Tokio keep their love alive in the face of such utter weirdness?

(Source: Juné Manga)