The Gamer

is a manhwa series written by Sung Sang-Young and illustrated by Sang-Ah.

Plot
Han Jee-Han, a normal high school student, suddenly develops a special power where his entire world is shifted into a game-like setting. He can see the power levels of people, look at the stats of a seemingly normal item, get abilities and even level up! Follow Han Jee-Han as he discovers how to use this power and the world of Ability users, which forces him to become stronger so he will not get caught and be used as a tool for their mana consumption.

Official

 * Naver