The protagonist, once an ordinary office worker, borrowed money from loan sharks due to a family member's sudden critical illness. The debt spiraled out of control, eventually costing him his job, home, and dignity. At his wit's end, a mysterious system activates, offering to help him repay all his debts by completing a series of dangerous missions.

The protagonist, once a hopeful young person, is framed by his best friend and lover, leading to his imprisonment. After being released, he finds his family has committed suicide due to shame and pressure, while the real culprits remain free. At his darkest hour, a revenge system appears, offering detailed plans and resources for vengeance.

The protagonist, an ordinary college student, is accidentally transported to a fantasy world filled with magic and monsters. Labeled the "weakest hero" due to his lack of talent, he is deemed useless. However, a hidden system activates, informing him that his power comes from failure. Each failure grants him new abilities or enhances existing ones.