I achieved my cozy life of a seventh-grade civil servant through a lot of hardships and nights of blacking out, so I was looking forward to the weekends where I could relax and have fun, but that night…

Is this Baek Rijin, the main character of the novel?

When I returned to my senses, I discovered I was in the novel I was reading. Did a seventh-grade civil servant like me became the spoiled young master of the great Jaegal family?! A side character, who has received excessive investments and love since he was young, and now going through a stormy period of his life… The spoiled young master of the Jaegal Family, whom the Blood Demon Cult would annihilate ten years later!

(Source: KakaoPage, translated)