Yoru no Shita Machiawase

Our heroine, whose name no one in school can remember, can’t decide what’s weirder—that the most popular guy in school, Koga-kun, wants to be her friend...or that he insists he’s an alien. But one thing’s for sure—he knows her name, and doesn’t seem ready to let her go through high school anonymous!
(Source: Kodansha USA)