Chaegeul Ilgeumyeon Gyeongheomi Ssayeo

Jongsuk is the pinnacle of mediocrity, with nothing to show for himself except his penchant for reading. One day, he finds a mysterious book at his favorite used book store. The book "tells" him to write about his experience in its blank pages, and in return shows him a related piece of information. Little did he know, the passages Jongsuk read in the books transferred right into his system, endowing with new abilities he never thought possible.
(Source: Pocket Comics)