The Regressed Extra Becomes a GeniusHoegwihan Extra-ga Cheonjaega Doem; 회귀한 엑스트라가 천재가 됨; The Returned Extra Becomes a Genius; The Regressed Extra Becomes a Genius; O extra regressado é um gênio; 回帰した脇役は世界を救う

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.