Ikenai Kanojo no Otetsudai

Youhei Terada is an average high school student whose only talent is his ability to see ghosts. One night, he meets "Rooftop Rinko-san," a ghost who resides on the rooftop of his school. Because she was unable to make any friends during her life, does that make her the type of ghost who won't let anyone who meets her leave the rooftop...? It's the story of a hilarious friendship between man an incompetent ghost girl!

(Source: Hakusensha, translated)