Kami nomi zo Shiru Sekai

Synopsis

Elsie has become a fan of the popular teen idol Kanon Nakagawa. However, Keima shows no interest in her, explaining the flaws of idols in real life compare to video game heroines. Unknown to both of them, Kanon just so happens to be a classmate of their class and is coming back to school. When Kanon meets Keima on the school roof garden, she is shocked and depressed to learn Keima has no idea who she is and proceeds to tase him repeatedly. Elsie detects an evil spirit inside of Kanon, being Keima's next target. Kanon vows to make Keima acknowledge her and make him her fan by holding a private concert just for him, but Keima ignores her, as he believes it is a trap as boys should be chasing girls and not the other way around. The next day, Kanon holds another concert for Keima which he ignores again. A sad Kanon suddenly starts to disappear in front of Keima and Elsie.

(Source: Wikipedia)