Keima Katsuragi is the main hero of The World God Only Knows. He is a 17-year-old student known throughout the internet as "The Capturing God" for his unrivaled mastery of Galge. He vehemently claims to have no interest in reality or 3-D girls, instead preferring the company of his video game characters. Therefore, while a legend in the gaming world, in real life he's an anti-social otaku whom most students avoid. Despite his lack of real world social skills, he demonstrates immense confidence and remarkable intelligence, and is in fact at the top of his class in every subject except PE.
His life is changed completely one day when he unwittingly accepts a contract from hell that pairs him up with Elsea to capture evil spirits that are possessing girls in the real world. Using his vast knowledge and experience gained from playing hundreds of dating sims, Keima must win the hearts of young women in spite of his disinterest in reality.
At the start of the series, he's isolated, rude, thoughtless and inclined towards abusiveness. However, as time goes on, he goes through some remarkably steady development and shows a surprising amount of concern for the girls he captures.