Ian Percus, the second son of a countryside Viscountcy.
One day, he received a love letter from the future.
'If we don't protect the future, the world will perish.'
With an ominous warning scribbled by someone

I, a mere con artist, was unjustly imprisoned in Tantalus, the Abyssal Prison meant for the most nefarious of criminals, where I met a regressor.
But when I used my ability to read her mind, I found out that I was fated to die in a year...
and that the world would end 10 years later.

To save the hopeless Dark Fantasy World, I held back my tears and destroyed the world, then killed the Demon King and returned.
Now, Iam trying to save the world using the aSystema I gained as a aRegressoras Privilegeaa| But the Main Heroines have also awakened their own memories of the previous timeline.
God damn it.