Substitute Mobs Cannot Escape

Lilyu reincarnated as a mob character in a light novel.
She calls her knowledge of the original story “future vision'' and by being ahead of the curve, she steals the credit from the original protagonist.
However, since she entered the world after the original story ended, she was in debt, broke off her engagement, and her life fell apart.
At that time, Albert, the main character of the original story, appears…
This is a story about the original protagonist x mob characters.
Please be careful because it feels like a “obsession attack'' → → uke with a completion in the attack, and only the attack has a happy ending.