The World God Only Knows (神のみぞ知るセカイ), abbreviated as Kaminomi (神のみ), is a Japanese manga series written and illustrated by Tamiki Wakaki. It was originally serialized in Shogakukan's Weekly Shōnen Sunday from April 2008 to April 2014, with its chapters collected in 26 volumes. The manga was adapted into three anime television series by Manglobe, which were broadcast in Japan from October 2010 to September 2013. In North America, the anime series were licensed for English release by Sentai Filmworks.
Plot
Keima Katsuragi, a second-year high school student, is an avid player of gal games (video games that involve interactions with anime-styled pretty girls). He is known on the Internet as "The God of Conquests" (落とし神) for his legendary skills to be able to "conquer" any 2D girl in games. However, in his actual school life, Keima is called otamega (オタメガ), a derogatory portmanteau of the two words otaku (オタク) and glasses (メガネ).
At the start of the series, Keima receives an e-mail offering him a contract to "conquer" girls and, thinking it is an invitation to a game challenge, he accepts. In response, a cute demon from Hell named Elsie appears: a Spirit Hunter. She asks for his cooperation to help her in catching the evil spirits that have escaped to the Human Realm: the "Loose Souls", which were once Old Demons from Hell. These evil spirits hide themselves inside the hearts of girls, feeding off the hosts' negative emotions to replenish their power and strength, thus becoming whole demons once again (and in turn, the host becomes an empty shell of a person).