The World of Narue

This is a story about a girl named Narue who happens to be a schoolgirl who happens to be a space alien. Kazuto is the boy who ends up falling in love with her and together they end up having some very wild and wonderful experiences including meeting alien assassins, other alien beings, alien spaceships that turn into people, and all the "regular" people that end up getting involved with them.

It's a really cute series.