Sole reader of a novel called "Three Ways to Survive in an Apocalypse"; sarcastic and salty, when offended; doesn't talk much with unfamiliar people, but likes those who are close to him; introverted; lived a boring life; traumatized by the fact that his mother killed his abusive father, his mother is now in prison.

Sole reader of an unpopular novel

Yoo Joonghyuk's speech is concise and blunt, often to the point of rudeness. He becomes explicitly rude and threatening when speaking to individuals who irritate him, or who are powerful unknowns.
Over the course of his regressions, aside from becoming more open to cruelty, he becomes extremely calculating and cold. He kills those he deems threats and supports those who he believes can aid him and never goes for a compromise.