Avatar

The protagonist is your average, everyday, Korean school student. That is, if not for his obsession that aliens live on Earth disguised as humans.
Much to his surprise, he was right, the aliens play a game called "Avatar" where they take human form and live human lives. And because of a glitch he caused in their system, now his very life could be at risk.
Now he needs the protection of an Admin of the "Avatar game" or else he could very well die!
(Source: MU)