Mook is a classmate the four protagonists meet at Refund High School. He is shrouded in mystery and not much is known about him at the moment, but he will definitely become a more prominent character in the webtoon. From speculation, Mook is probably some sort of deity, royalty, or the like as he receives tons of gold coins and animal sacrifices from the living. He lives in the teacher dorms with Mr. History Teacher maybe in order to keep an eye on Mook at all times. It is also inferred that Mook committed suicide in his past life and that Mr. History Teacher doesn't seem to want him to regain his memory of his past life. Fun fact, Mook turns into a huge dragon whenever it rains :)

Mook regards himself as of higher class than the others, acting coldly and unfriendly towards Aru. Despite this, he doesn't fail to get elected as class representative even though he didn't particularly want the position.

Please note that the audition lines are all continuous in one scene.

Medium to Medium-High Voice I picture his voice two ways. Either a toned down Death the Kid (Eng): https://youtu.be/-Tj3PAjro3Y?t=35s or Shihou (Jap): https://youtu.be/t5Bs6JR0Wkc?t=27s  Just kind of condescending and posh...and tsundere