From the Start, a Fake Heir: Trading Lifespan for Experience

Lin Ran played a text-based game and chose to enter under an assumed identity, becoming a stand-in for Lin Tianhan, the Prince of Zhenbei's son. Later, Lin Fan realized something was off. While the other players were diligently completing quests and leveling up, he had a Lifespan Experience System. As long as he spent his lifespan, he could increase his strength without limit. And when he killed an enemy, he could steal their life force.