The Regressed Extra Becomes a Genius

Read manhwa The Regressed Extra Becomes a Genius / 회귀한 엑스트라가 천재가 됨
The story delves into the life of Kim Seon-woo, who got pulled into a famous novel and decided to live a quiet life as a side character. One day, the protagonist of said novel died… “…Do you expect me to believe this?” He ends up regressing back in time – back to his first day within the novel.