Demon Diary (ko: 마왕일기 mawang ilgi, "Diary of a Demon King") is a 7-volume soonjung Japanese style manhwa (Korean comic) illustrated by Kara.

"Kara" is the name of the duo team consisting of Kim Yoon-gyeong and Jeong Eun-sook.

Demon Diary was originally published by Sigongsa and has been licensed in North America by Tokyopop.

Lee stopped writing, because he had to prepare for the upcoming high school exams.

Because of his actions during the Hangma War (which are not elaborated upon), he became known for his cruelty and incredible power.